Folia Geobotanica 33: 241-316, 1998
AN ACCOUNTOF THESPECIES OF POTAMOGETON
L.
(POTAMOGETONACEAE)
Gerhard Wiegleb1) & Zdenek Kaplan2)
1) Department of General Ecology, BTU Cottbus, POB 10 13 44, D-03013 Cottbus, Germany;
tel. +49 355 692291, fax +49 355 692291, E-mail wiegleb@tu-cottbus.de
2) Institute of Botany, Academy of Sciences of the Czech Republic, CZ-25243 Pruhonice, Czech Republic;
fax +420 2 67750031, E-mail kaplan@ibot.cas.cz
Keywords:Descriptions,Hybrids,Key to species,Specieslist, Synonyms,Taxonomicproblems
Abstract:An accountof thetaxonomyof thegenusPotamogetonL. withspecialreferenceto speciesdescription
anddelimitationis presented.A key to the species is given, basedas faras possibleon vegetativecharacters.
Detaileddescriptionsare providedfor a total of 69 species which are regardedas sufficientlywell known.
Specialemphasisis laid both on a completelist of relevantcharactersas well as on the judgementof their
respectivediagnosticvalues.All importantsynonymsarelistedallowingdirectaccess to mostof the relevant
taxonomicandfloristicPotamogetonliterature.50 confirmedhybridsare listedandassignedto theirputative
parentspecies.Questionswith respectto the taxalistedareformulatedin noteson eachof the species.A more
generalview andquestionson futurePotamogetonresearchare summarizedin the conclusions.
"It is to be regretted that we never arrive to the truth but through some mistake or another"
(J.O. Hagstrom 1916)
INTRODUCTION
Since the days of GRAEBNER
(1907) and HAGSTROM
(1916) no comprehensivetaxonomic
treatmentof the genus Potamogeton L. claiming worldwide validity has been carriedout.
The work of GRAEBNER
(1907) was an attempt to compile all the known taxonomic and
phytogeographicinformationaboutthe genus, althoughP. Graebnerhimself never carriedout
importanttaxonomic work on the genus Potamogeton.In contrast,J.O. Hagstrom'streatment
was based on 15 years of intensive anatomicaland morphologicalstudies of all specimens
accessible to him. Hagstrom examined ca. 90% of the species known at that time. The
comprehensiveness of his work is still unrivalled. Hagstrom's approach to infrageneric
classification and species circumscriptionwas acknowledgedonly recently both by WIEGLEB
(1988) and LES& SHERIDAN
& (1990b). Anotherearly 20th centuryauthor,A. Bennett,had
a worldwideknowledge of the genus, but he never produceda comprehensivetreatment.His
work is scatteredin numerous,often contradictory,notes.
Since the time of Hagstrom'swork a lot of new informationhas become available.Several
papers deal with various aspects of the genus. Seed anatomywas treatedby AALTO
(1970),
general morphology by TOMLINSON
(1982), chromosome numbers by LES (1982) and
HOLLINGSWORTH
et al. (1998), pollen morphologyby SORSA
(1988), stem anatomyby WIEGLEB
(1990c), and flavonoid chemistryby LES& SHERIDAN
(1990a). However, the informationon
242
G. Wiegleb&Z. Kaplan
species distributionand variation in different parts of the world is still quite inconsistent.
Westernand CentralEuropeanPotamogeton taxonomy had reached a certain stability at the
end of the 19th century.The work of PRESTON
(1995) for the British Isles can be regarded
as a culmination of this tradition in the degree of precision and completeness. In North
America (FERNALD1932, OGDEN 1943, HAYNES1974, REZNICEK& BOBBETTE1976) and
Japan(MIKI1937) a state of knowledge comparableto Europehas been reached.In Australia
(ASTON 1973), South America (TUR 1982), South Africa (DANDY 1937, OBERMEYER
1966,
SYMOENSet al. 1979), and Russia (YUZEPCHUK1934, TZVELEV1987, KASHINA 1988,
VOLOBAEV
1993) a significant effort has been made without, however, solving important
taxonomicandnomenclaturalproblems.Worldwideinformationon distributionandtaxonomy
is only available for five of the widespreadspecies (HAYNES
1985, WIEGLEB
1990a,b).
The following treatmentis regardedas a first step towardsa worldwide monographof the
genus Potamogeton. The aims are to constructa key to all "sufficientlyknown species" and
to give descriptions, as comprehensive as possible, for all those species according to the
presentstate of knowledge. In additionquestionsareformulatedas a basis for futureresearch.
METHODS
Data base
An assessment of the validity of the taxa recognizedbelow is based on the following work
that has been conducted since 1985:
(1) Herbariumstudies. Extensive herbariumstudies were carriedout in the course of the
description and re-evaluation of several Potamogeton taxa (KADONO
& WiEGLEB1987,
WIEGLEB
1990a,b, 1993), the work in connection with Flora Malesiana (WIEGLEB,
unpubl.)
and the work on the contributionof Bohemianbotaniststo Potamogeton taxonomy (KAPLAN
1997). Additionalstudies were carriedout directlyfor the purposeof this paper.Potamogeton
of B, BM, BREM, BRNM, BRNU, CTES, GLM, HBG, JE, K, L, M, MP, OLD, OLM, OP,
PR, PRC, ROST,W, and WU were checked completely,and additionalloans were made from
A, AAU, ABD, BKF, BOL, BP, BRI, C, CANB, CGE, E, F, G, GAT,GOET,H, HAL, LAE,
LD, MICH, MO, NH, NY, P, PERTH,PH, S, SING, TAA, TAI, TFC, TI, TUB, U, UC, UPS,
WAG, WRSL, and ZT.
(2) Field surveys. The collection of specimens was carriedout in variouspartsof the world
(G. Wiegleb: the Atlantic Islands, Western,Central and SouthernEurope, including Great
Britainandthe MediterraneanIslands,Japan,Argentina;Z. Kaplan:Western,Central,Southern
and EasternEurope, Siberia, SouthwesternAsia). Specimens are deposited in the herbariaof
the respective authors(G. Wiegleb: Museum fiir Naturkundeund Vorgeschichte,Oldenburg,
Germany;Z. Kaplan:Instituteof Botany, Pr'uhonice,Czech Republic).
(3) Field ecological studies.The variationof varioustaxa(G. Wiegleb:P alpinus,P. natans,
P. distinctus, P. wrightii; Z. Kaplan: P. pusillus, P. trichoides, P. pectinatus) was studied,
including also experimental studies (KAPLAN,unpubl. data).
(4) Studyof stem anatomy.The stem anatomyof varioustaxawas studiedin detail(WIEGLEB
1990c). The collection of slides with preservedcross sections is kept at the biological collection
of the BrandenburgischeTechnische Universitat,Cottbus.
(5) Literaturesurvey. Based on the data bases accumulatedindependentlyby both authors
in the course of this survey,more than 2000 names were checked for their validity,legitimity,
correct spelling and exact citation (Z. Kaplan).
Taxonomyof Potamogeton
243
Taxonomic concepts
An open discussion on the respective taxonomicconcepts at each level of the taxonomical
hierarchyis regardedas crucial for a successful approachto Potamogeton.
Delimitation of the genus
In the present paper Potamogeton L. is regarded as one of two genera of the family
Potamogetonaceae, the second one being the closely related genus Groenlandia J. GAY.
Groenlandiadiffers from Potamogeton in the following aspects:
(1) Fruittype (having a drupe-like,instead of an achene-like, fruit in Potamogeton).
(2) Specialized type of hibernatingstructures(not found among the numerous types of
winter buds in Potamogeton).
(3) Predominanceof subopposite leaves throughoutthe stem (in Potamogeton occurring
in the floral region only).
(4) Absence of stipule-like appendages(subsequentlyreferredto as "stipules")on most of
the leaves with lateralones being producedonly on the involucralleaves (Potamogetonhas
axillary or adnate stipules on all leaves).
(5) Spikes bearingregularly(1-)2(-4) flowers only (comparedwith the 4 to many-flowered
spikes of Potamogeton).
(6) The uniquebasic chromosomenumbern= 15 (comparedwith n= 13 or rarelyn=14 found
in Potamogeton).
Classification into subgenera
Recently, several attemptshave been made to introducea thirdgenus Coleogeton (RCHB.)
LEs et R.R. HAYNES(LES & HAYNES1996), or more correctly Stuckenia BORNER(HOLUB
1997), based on a group of species formerlytreatedas subgenusColeogeton (RCHB.)RAUNK.
However, the reasons for separatingthis groupfrom the genus Potamogetonare not regarded
as convincing. Most of the charactersclaimed to be exclusive for Stuckenia occur also in
Potamogeton s.str.:
(1) Stipularsheaths, mostly fused for more than half of their length. Stipularsheaths are
constantly found in P. spirillus (in this species the fused portion is also longer than half of
the length), P diversifolius, P. bicupulatus,P. robbinsii and P maackianus, also in young
specimens of P alpinus, P. nodosus, P. distinctus,P wrightii, P gramineus and P. lucens.
(2) Channelled leaves (phyllodial leaves sensu RAUNKIAER
1896). Such kinds of leaves
are, however, regularlyproducedin P. natans, P oakesianus, P. diversifolius,P bicupulatus,
P. spirillus, P. octandrus, P. cristatus, P vaseyi, often also in P lucens, P. gramineus,
P thunbergiiand P. illinoensis. This holds even though "phyllodial leaves" cover a wide
range of leaf shapes.
(3) "Hydrophilouspollination".Pollination in Stuckenia, as inferred from the elongated
stigma, is claimed to be differentfrom "anemophilous"pollinationin Potamogeton.However,
epihydrophily(includinghydroautogamy;i. e. pollinationby means of two dimensionalpollen
transferrestrictedto the water/airinterface,eitherat the watersurfaceor on bubblesproduced
by submersedflowers during anthesis) occurs also in P acutifolius, P pusillus, P foliosus
and P lucens, all of them being member-sot Potaitnogetons. str.
(4) Higher ploidy level (particularlyhexaploidy).The distinctionin chromosomenumber
is not so clear as is sometimes stated. Higher ploidy levels have also been reportedfor
P crispus, P illinoiensis and P richardsonii.
244
G. Wiegleb&Z. Kaplan
(5) Hybridization. It is said not to occur between Stuckenia and Potamogeton. The
taxonomicallyunclearplant describedas P. nomotoensismay be a hybrid between members
of these respective taxa (P. natans and P. pectinatus), as it combines the typical characters
of both groups.
We are aware that Coleogeton (Stuckenia)representsa compact monophyletic unit which
differsfromPotamogetonin several charactersrelatedto floral biology (endodermisof U-type
in the flexible peduncle, elongated stigmas, specializedpollen type) and hibernation(forming
a special type of rhizomatousturion).However,we drawattentionto the fact thatthe endocarp
type A is found in both taxa (AALTO1970). As we consider the charactersused by LES&
HAYNES
(1996) andHOLUB
(1997) as insufficientfor genericdistinction,the traditionalconcept
of treatingColeogeton at the rank of a subgenus is adoptedhere.
Infrageneric classification and arrangement of species
The arrangementof species in the descriptivepartreflectstheirsupposedsystematicrelation.
It is based on cladistic analyses of all taxa based on the charactersavailable so far (KAPLAN,
unpubl.). Assumptions on the affinity of the species are generally outlined in the notes. No
formal groupingis adopted.
We are aware of the fact that a taxonomic revision at the level of sections and subsections
is also desirable. However, it cannot be carried out at present. Depending on the exact
delimitationof these taxa, a complete check of the nomenclaturehas to be carriedout. We
assume that the genus Potamogeton may be furthermoredivided into 5 sections, 1 in
Coleogeton and 4 in Potamogeton, which form naturalunits. The approximatenumberof
subsections is 22, 3 in Coleogeton and 19 in Potamogeton.
Species concept
A wide species concept is adopted in the following treatment.All Potamogeton species
studied in more detail so far with respect to vegetative morphology and life history exhibit
a wide range of phenotypic plasticity. It is presumedhere that this holds also for the rest of
the species. Therefore,the distinctionof a species requiresat least two independentcharacters
which remain stable over a largergeographicalarea and over a wide range of environmental
conditions.
Species with a limited geographicalrange differingby single charactersfrom an otherwise
variable species are generally not recognized. In some cases of broad-leavedspecies, taxa
with a limited geographicalareaarerecognized as they exhibit uniquecharactercombinations
(e.g. the southernspecies P. stenostachys,P parmatusand P. papuanicus). In total 69 species
are recognized and described. Unfortunatelythe total range of plasticity of most species of
the SouthernHemisphereis unknown.
Concepts of infraspecific units
A generalconcept of a taxonomic treatmentof infraspecificclassification has not yet been
developed. Most varieties and forms recognized by older authors refer to obvious
ecomorphoses and have no taxonomic value whatsoever.Exceptionally,they are important
insofar as they contain basionyms for the modern treatment.
However, some of the taxonomic entities mentioned in the synonym list with a question
mark, or in the notes which follow the descriptions,may be regardedin the future either as
allopatricsubspecies or as sympatricvariantsof the respective widespreadtaxon.
Taxonomy of Potamogeton
245
Hybrid concept
Hybridizationis, under certain circumstances,a frequentevent in Potamogeton and often
leads to easily recognizable biological entities. Because of their frequency and ecological
importance(WIEGLEB
1988) they have to be considered in any taxonomic treatmentof the
genus. Neglect could lead to misidentificationof a numberof specimens.
In total 50 hybrids are recognized here as being well establishedand distinguishablefrom
the respective parent species. Approximately20 furtherprobable hybrids proposed in the
literaturecannot be recognized without furtherstudy, in particularby experimentalcrossing
experiments. Many proposed hybrids, of which we were able to study the type specimen,
proved to representone of the parentalspecies only.
The correctnames of the hybridsare based on both putativeparentspecies. Synonyms and
notes are only given after the first-mentionedparent species. No descriptionof the hybrids
is given, as in most cases the hybrids are intermediateamong the putative parents.We are
aware of the fact that this is not true in all cases. Our list of "hybrids"contains three groups
of taxa, which cannot be operationallydistinguished:
(1) Confirmedhybrids, most probablyof recent origin, which are usually sterile, forming
no seeds, or at least no viable seeds (e.g. P. xnitens), or only exceptionally producingwell
developed fruits (best known in P. xangustifolius).We assume that this is the most frequent
case.
(2) Fertile intermediatesthat may in the future be regardedas species in their own right,
which are possibly of hybridogenousorigin in the past. P. xogdenii is the only memberthat
can be named at present. This case underlinesthe possible importanceof hybridizationfor
species formationin Potamogeton.
(3) Some special forms which are too rare to be judged finally, and which clearly do not
deserve the rank of a species. The identity of these forms has to be clarified in the future.
P. xnomotoensis,P xvaginans and P. xfaxonii belong to this group.
All hybrids of the second and thirdgroup are commentedupon in a respective note.
The key
The accountof the species is precededby an analyticalkey to the species. The mainpurpose
of the key is to elucidate the most importantcharactersthat are useful for distinguishing
between the species. Thus, the key providesa kind of definitionand delimitationof the species
considered as valid in the frameworkof this treatment.The key is an artificialone. It is not
intendedto key out assumed subsections or relatedspecies groups in total before proceeding
to the species themselves.
The key should enable the user to identify most of the species based on the typical variation
shown by their individuals, provided that the necessary diagnostic charactersare developed
on a specimen examined. The key cannot be used to identify all extreme morphotypes,nor
can it give access to incomplete and fragmentaryherbariumspecimens. As far as possible,
it is based on charactersof vegetative morphology,in particularshape, size, and venationof
the submergedleaves. These are the charactersthat are available in most cases.
246
G. Wiegleb & Z. Kaplan
An account of the species
General arrangement of characters
The structurefollows the general patternas listed below:
(1) Name
(2) Citation
(3) Importantsynonyms
(4) Rhizome:shape,life cycle
(5) Stem:shape,life cycle
(6) Submergedleaves:lamina:shape,size, colour,venationandotherspecialfeatures;petiole
(7) Intermediate
leaves (if developed);shortcharacterization
(8) Floatingleaves (if developed):lamina:shape,size, venationandotherspecialfeatures;petiole
(9) Stipules:shape,size and specialfeatures(if necessaryseparatefor leaf types)
(10) Peduncles:size and shape
(11) Spikes:shapeand size (if necessaryseparatefor spiketypes)
(12) Flowernumber;numberof carpels
(13) Fruits:size, specialfeatures
(14) Stem anatomy:stelartype, endodermistype, interlacunar
bundles,subepidermal
bundles,pseudohypodermis
(15) Distributionin outline
(16) Hybridsincludingtheirimportantsynonyms
(17) Notes
The list of synonyms is restrictedto those used in importantfloras or reference works as
accepted by the respective authors. For example, most taxa treated at the species level in
GRAEBNER(1907) and HAGSTROM(1916) can be assigned to species we recognize.
Furthermore,names generally cited and names published in recent years are recognized. In
order to save space, the list is confined only to "moreimportant"names, mostly at the level
of a species. Names of subspecies are sometimes included as they are generally neglected,
but may become importantfor future infraspecific treatment.In the case of an uncertain
assignment of a name a question mark is added.
The description of morphology and anatomy is carried out with special emphasis on
vegetative diagnostic characters.The descriptive terms of morphology, population biology
and anatomy are outlined below. The notes usually concentrateon two importantquestions:
Does the respective taxon exist and which is the correctname? What informationis lacking
to answer these questions?
Information excluded
The following items were deliberatelyexcluded from the account of the species:
(1) Informationon typification and the deposition of type specimens. Types are often not
designated, and in case of designation contradictoryinformationis available in many cases.
This implies a certain instability of nomenclature.
(2) Chromosome numbers. Overviews of published chromosome numbers can be found
in LES(1982) and more recently in HOLLINGSWORTH
et al. (1998). The data are excluded
from the descriptions for several reasons. Only for ca. 30 species are two or more
methodologically reliable counts available. All reliable counts originate from the Northern
Hemisphere. Of at least 20% of the reliable counts we are not sure to which taxon of the
present treatmentthey actually refer.
Taxonomy of Potamogeton
247
(3) Further information about several floral and generative characters, which have been
regarded as important by earlier authors, e.g. information about sepaloid connectives or
additional information about size, shape, and colour of fruits.
Descriptive terms of vegetative morphology
Descriptions of morphological characters and life histories in the taxonomic treatment of
Potamogeton are often inexact. This is due to the fact that all Potamogeton species have a
complex modular organization difficult to describe both in terms of classical and functional
morphology. A fully satisfactory description of all morphological characters regarded as
taxonomically important would be very space consuming. If possible, the nomenclature on
branching, longevity of plant parts, overwintering structures, seasonality, etc. as proposed by
BRUXet al. (1989), WIEGLEB
& BRUX(1991), and WIEGLEB& KADONO(1989a,b) is adopted.
As some simplifications were necessary, some explanations are given below.
Shoot types. In Potamogeton two different basic shoot types occur, namely "vertical
shoots" [VS] ("erect shoot" sensu TOMLINSON1982, including also the lateral "renewal
shoots") and "horizontal shoots" (as lower and upper horizontal shoots [LHS, UHS]), which
differ in leaf insertion and vegetative anatomy (TOMLINSON 1982). This differentiation is
visible in all species, despite the fact that individual plants can change their growth pattern
in an opportunistic way. Only for the sake of comparability with general Potamogeton literature
do we use the term "rhizome" in the descriptions for the lower horizontal shoot, regardless
whether it is actually stoloniferous, rhizomatous, or a complex of differently shaped parts. In
the descriptions we also use the term "stem" characterizing the main axis of the vertical shoot.
If necessary we use the terms "horizontal shoot" and "vertical shoot" to remain morphologically
exact.
Branching pattern. A complete account on branching pattern cannot be given here, as
even terms like "sympodial" and "monopodial" are not well-defined in Potamogeton and
would require explanation at length. If we use expressions like "stem unbranched" we indicate
that the species (e.g. P. alpinus) develops no renewal shoots below the pseudo-opposite
involucral leaves. But it may produce turion-bearing upper horizontal shoots in some cases,
in particular at the end of the growing season.
In principle, branching analysis is also important for a proper description of the inflorescence
types. As the "inflorescence types" sensu HAGSTROM
(1916) are not known for all species,
we do not mention them. We use simple descriptive terms like "apical" or "lateral" to
characterize the position of flowering parts, well knowing that these terms are imprecise
without having identified the primary spike. In accordance with TOMLINSON
(1982) we use
the term "inflorescence" for the "spike-peduncle unit" as a whole. This contrasts with
HAGSTROM'S
(1916) use of this term.
Longevity and hibernation. We avoid undifferentiated expressions like "annual" and
"perennial". Terms relating to longevity always refer separately to below-ground or
above-ground parts of an individual. Additionally, remarks on seasonality are given, if
information is available. For example, in P lucens the rhizomatous part of the LHS is at least
biennial, mostly perennial, while the above ground vertical shoots are often short-lived and
summer-green. The species has a seasonal development throughout its range. Unfortunately,
such information is in most cases not available for Southern Hemisphere species.
We distinguish various types of "winterbuds" or "propagules" (see RAUNKIAER1896),
which in all cases serve several functions in the life cycle of an individual plant (hibernation,
248
G. Wiegleb & Z. Kaplan
droughtresistance,shortrangedispersal,etc.). We distinguishbetween winterbudson vertical
and horizontalshoots:
(1) Winterbudson VS are found as axillaryor apical fusiform "turions",which are mostly
dormant (e.g. in P. pusillus), as non-dormantaxillary turions of varying shape (e.g. in
P. crispus), or as unspecialized, non-dormant,axillary, short shoots (e.g in P. natans and
P. praelongus).
(2) Winterbudson LHS are found mostly as dormant apical turions on stoloniferous
horizontalshoots (e.g. in P. alpinus, also on upperhorizonatalshoots), as rhizomatoustubers
(e.g. in P.pectinatus), and as turion-tubercomplexes, mostly on rhizomatouslower horizontal
shoots (e.g. in P. lucens). Also unspecializedleafy verticalshoots can be regardedas winterbuds
in some species (e.g. in P. amplifolius).
Leaf description. Special emphasis is paid to the descriptionof the leaves. Descriptive
terms of leaf structureare always expressed in comparisonto other aquaticplant leaves (and
not terrestrialmesophyte leaves, as is often found in the literature).The fact that submerged
leaves are membranousand translucentis taken for granted.The typical submergedleaf is
found in the middle of the stem. The lower submergedleaves are often different in shape,
which is acknowledged if they make up a significant portion of the leaves. The upper ones
are often developed as "intermediate leaves". These leaves can be independently
"intermediate"between submergedand floating leaf as to shape, structure,and petiolation.
They may sometimes be presentin the absenceof truefloating leaves. This fact usuallyresults
from a phenotypicreaction to varying water levels.
Descriptive terms of stem anatomy
We regardstem anatomicalcharactersas useful informationwith respect to the taxonomic
arrangementof the species, and also the identificationof fragmentaryherbariumspecimens
(see HAGSTROM
1916, TUR 1982, WIEGLEB1990c). However,the anatomicalcharactershave
to be treatedwith great care. There is a lot of variationwithin species, often even within one
individualspecimen. Particularlyin the studyof herbariumspecimens, when only those shoot
types and parts available by chance can be studied, results of the study of a single cross
section must not be overestimated.
The stem anatomical charactersreportedhere refer to internodes on the upper parts of
stems. The following charactersare regardedas taxonomicallyimportant:
(1) Type of stele, distinguishingamong the proto type (with more than 8, usually 10-14
free vascular bundles), the trio type (or eight bundles type, if necessary with additional
informationon the numberof phloema, 1 or 2, in the trio bundle), the oblong type (with the
3 separatedparts themselves containing 1-3 bundles), the four bundles type, and finally the
circular type (or one bundle type). In a few cases additional characters like shape and
sclerenchymatizationof the stele are listed.
(2) Cell shapeof the endodermis(which is eitherof U or 0-type, or intermediateU-0-type).
A furtherpossible differentiationaccording to the strengthof the cell walls is attributedto
the developmentalstage of the individual.
(3) Presence of interlacunarbundles, with additional informationon number (including
completeness of rings) and size.
(4) Presence of subepidermalbundles, including numberand size.
(5) Presence of the pseudohypodermis,including numberof cell layers.
Taxonomy of Potamogeton
249
KEYTO THESPECIES
la
lb
2a
2b
3a
3b
4a
4b
5a
5b
6a
Stipulesof submergedleaves adnatefor most of theirlengthto the leaf base, leaf laminaarisingat the
top of the stipularsheathwhich surroundsthe stem abovethe node;submergedleaves alwayslinearto
broadlylinearor rarelylanceolate............................
2
Stipulesfree from the leaf base or almost so, leaf laminaor petiole arisingdirectlyfrom the node;
submergedleaves linearto broadlyovate...........................
13
Leaves serrulateor denticulateat margins,1.1-8.0 mm wide, 7-25 times as long as wide, auriculateto
roundedat the base.............................................................
3
Leavesentireat margins,0. 1-2.5(-5.0) mm wide, 15-600 timesas long as wide, straightat the base. . 4
Submergedleaveslanceolate,graduallytaperingto apex,stiffish;specializedaxillaryandapicaldormant
turionsdeveloping;scatteredinterlacunar
bundlespresent......
36. P. robbinsii
................
Submergedleaves linear,with ? parallelmargins,abruptlytaperingat apex, ? lax; specializeddormant
turionsnot developing;interlacunar
bundlesabsent......
37. P maackianus
...................
Stipules fused with the leaves for 6-65(-140) mm; floating leaves always absent; inflorescences
monomorphic;
peduncles20-200(-450) mmlong;spikeslong cylindrical,(13-)20-75 mmlong in fruit;
submergedleaves tubularwith airchannelsborderingthe midrib;fruitsconvex on sides, withoutlateral
keels;endodermisof U-type,rarelyof 0-type ...........
...............................
5
Stipulesfused with the leaves for 0.3-6.0 mm;floatingleaves often present;inflorescencesdimorphic
to trimorphic;peduncles 1-32 mm long; spikes subgloboseto cylindrical,2-28 mm long in fruit;
submergedleaves ? flat with lacunaeborderingthe midrib;fruitsconcaveon sides, with distinctlateral
keels;endodermisof 0-type .1......................................................
1
Stipulesconnateandtubularat the base whenyoung,marginsof the openportionbrown;flowerwhorls
in spikemarkedlyremoteat anthesis;leavesof the mainstemobtuseat apex;maturefruits(1.9-)2.2-3.5
mmnlong
............................................................
6
Stipulesopen andconvolutealongtheirentirelength,marginsof the openportionwhitish;flowerwhorls
in spikecontiguousat anthesis,laterremote;leavesof themainstemacuteto obtuseor subretuseat apex;
maturefruitsmostly 3.0-4.7(-5.1) mm long ...........
................................
7
6b
Leaves0.3-1.2(-1.9) mm wide, (50-)100-300 timesas long as wide, obtuseto subacuteon side shoots;
fruits(1.9-)2.2-2.8(-3.2) mm long; apex of ligule obtuseto rounded;stipularsheathof leaves on main
stemnot inflated..............
66. P filiformis
Leaves 1-3 mm wide, 20-50 times as long as wide, always broadlyobtuse;fruits(2.8-)3.0-3.5 mm
long;apex of ligule subretuse;stipularsheathof leaves on mainstem ofteninflated.
...............................................................
P67.Pamblyphyllus
7a
7b
Leavesalways obtuseto subretuse;fruitswithouta distinctbeak...........................
Leavesmostlyacuteto acuminate;fruitswith a distinctbeak ..
8a
8b
Leavesstronglyrecurvedat the top;pedunclesshort,20-50 mm long ....
........ 65. P recurvatus
Leavesnot recurvedat the top;peduncles30-170(-200) mm long..........................
9
9a
Leavesobtuseat apex;peduncles30-150 mm long; stipularsheathof leaves on mainstem(especially
the lower ones) very broad,up to 10 mm wide, 30-70 mm long; interlacunarbundlesin (3-)4 circles
63. P vaginatus
.................................................................
At least some leaves clearly subretuseat apex;peduncles100-170(-200) mm long; stipularsheathof
leaves on main stem narrower,1.5-4.0 mm wide, 20-30(-40) mm long; interlacunarbundles in
1 incompletecircle ..........
64. P subretusus
9b
8
10
lOa Leaves of the main stem less thantwice as wide as those on the branches;fruitswith a beakup to 1.2
mm long, rhizomatoustubersmostlydeveloping..........
68. P pectinatus
lOb Leavesof the main stem morethantwice as wide as those on the branches;fruitswith a beak less than
0.5 mm long;rhizomatoustubersnot developing........
69. P striatus
250
G. Wiegleb & Z. Kaplan
1la
(4) Adnateportionof the stipulemostlylongerthanfree ligule, fused with the leaves for 1.5-6.0 mm;
fruitswith a dorsalkeel and smoothlyroundedsides, lateralkeels absent.....
....... 60. P spirillus
1lb Adnateportionof the stipulemostly shorterthanfree ligule, fused with the leaves for 0.3-3.5(-4.0)
mm;fruitsusuallywithtwo lateralentireto dentatekeels in additionto the dorsalkeel ....
...... 12
12a Submergedleavesfromthe middlepartof stem(0.3-)0.5-1.5 mm wide, 20-180 timesas long as wide,
floatingleaves (7-)13-40 mm long .......
61. P diversifolius
.................
12b Submergedleavesfromthe middlepartof stem0.1-0.4(-0.5) mmwide, 190-500 timesas long as wide;
62. P bicupulatus
floatingleaves 6-23(-28) mm long........................
13a (1) Leaf marginsserrate,with teetheasily visible to the nakedeye; fruitsadnateat base;beak at least
half as long as the rest of the fruit;submergedleaves (3-)5(-7)-veined; floatingleaves alwaysabsent
.
35. P crispus
................................................................
13b Leaf marginsentireor minutelydenticulate,with teethnot or scarcelyvisible to the nakedeye; fruits
freeatbase;beakmostlymuchless thanhalfas longas therestofthefruit;submergedleaves1-41-veined;
14
floatingleaves absentor present...................................................
14a All leaves filiformto linear,with parallelsides, or sometimeslinear-lanceolate,
(13-)18-110 timesas
long as wide, mostly0.1-6.0, rarelyup to 9.0 mm wide, all sessile, submerged,entireat margins;stele
of oblongor circulartype (in P polygonus of protoor reducedtriotype).15
14b Mostlyall, butat least floatingleavesnarrowlyellipticalto orbicular,withconvex sides, 1-13 timesas
long as wide, 4-80 mm wide, sessile and/orpetiolate,submergedand/orfloating(or rarelyemersed
when semiterrestrial),
entireand/ordenticulateat margins;stele mostly of proto,trio or four bundles
type, sometimesof oblongor circulartype.33
l5a
Leaveswithbothlateralveinsandmanyadditionallongitudinalsclerenchymatous
strands;stemstrongly
compressedor flattenedto terete;stele of oblongtype, rarely(P polygonus)of protoor reducedtrio
type.16
15b Leaveswith 1-4 lateralveins on each side of the midribwithoutadditionalsclerenchymatous
strands;
stemtereteor subtereteto slightlycompressed;stele mostlyof circulartype, sometimesof oblongtype
24
..........................................................................
16a Leaves (5-)7-9-veined, 3-6(-9) mm wide, with broadto very broadrows of lacunaeborderingthe
midrib,acuminateat apex; strandsin the leaf margins stronglysclerenchymatous,
persistingas fibres
38. P polygonus
. ...............................................................
16b Leaves 3-5-veined (5-7(-9)-veined in P oxyphyllus),mostly 1.2-5.0 mm wide, with narrowrows of
lacunae borderingthe midrib, acuminateor acute to obtuse, rounded or mucronateat apex;
sclerenchymatous
strandsin the leaf marginsalmostof the same strengthas the otherleaf veins . . 17
17a Leaves (1.8-)2.0-5.4(-6.0) mm wide, with 16-34 sclerenchymatous
strands(only (2-)8-16(-20) in
P oxyphyllus);fruits(2.8-)3.0-5.5 mm long.........................................
18
17b Leaves 1.2-2.5 mm wide, with 8-16(-20) sclerenchymatous
strands;fruits2.1-3.5 mm long ..... 23
18a Stemterete,0.3-0.6 mm in diameterthroughoutthe shoot ...............................
19
18b Stem stronglycompressedto flattened,(0.4-)0.6-3.4 mm wide (in P compressusexceptionallyup to
4.8 mm wide), distinctlybroadenednearthe nodes.21
19a Leaves with (2-)8-16(-20) sclerenchymatousstrands, 5-7(-9)-veined, linear to narrowly
linear-lanceolate,
acuminateat apex;pseudohypodermis
absent.......
............. 46. P oxyphyllus
19b Leaves with 20-32 sclerenchymatousstrands, (3-)5-veined, linear, acute to obtuse at apex;
pseudohypodermis
2-3-layered.20
20a Leaves25-90(-130) mm long, obtuseat apex.
20b Leaves85-200 mm long, acuteat apex.40.
.
.39.
P ochreatus
P furcatus
21a Peduncles3-15(-26) mm long;spikesalmostglobose,4-8 mm long in fruit,with (I-)2(-3) whorlsof
flowers;stipules10-21(-29) mm long;flowerswith l(-2) carpels......
........... 41. P acutifolius
Taxonomy of Potamogeton
251
21b Peduncles(19-)28-100 mm long; spikes cylindrical,15-33 mm long in fruit, with 5-11 whorlsof
flowers;stipules(16-)20-55 mm long;flowerswith (1-)2(-3) carpels.....
.................
22
22a Fruitsobliquelyandnarrowlyobovatein outline,3.4-4.0 mm long,beakrecurved,leaves(3-)5-veined,
stipulessoon erodingto fibrousstrandsat the apex ..........
42. P compressus
...............
22b Fruitsquadratelysuborbicular,4.0-5.0(-5.5) mm long, beak nearly erect, leaves 3-veined, stipules
persistentandgenerallyintactthroughoutthe season.........
43. P zosteriformis
...............
23a (17) Leaves 1.5-2.5 mm wide, acuminate;fruits2.8-3.5 mm long;dorsalkeel distinct.
44. P manchuriensis
..............................................................
23b Leaves 1.2-2.0 mm wide, roundedand mucronateat the apex; fruits2.1-3.0 mm long; dorsalkeel
indistinct..
.
.
45. P sibiricus
24a (15) Rhizomelong andcreeping;inflorescence1 or rarely2 in terminalposition;peduncles15-240 mm
59. P. confervoides
long;leaves filiform,0.1-0.5 mm wide.................................
24b Rhizomeshort or absent;inflorescencesusually more than 1 per shoot both in terminaland lateral
position;peduncles3-70(-80) mm long;leaveslinear,rarelyfiliform,0.3-6.0 mm wide ....
..... 25
25a Leavesobtuseto roundedat apex,oftenvery shortlymucronate,oftenwitha reddishtinge;stemrichly
branched;intermodes
mostlymuchshorterthanthe adjacentleaves ...........
54. P obtusifolius
25b Leaves acute,acuminate,mucronateat apex or graduallytaperingto a fine, almostbristle-likepoint,
reddishtingepresentor mostlyabsent;intemodesshorteror longerthanthe adjacentleaves.
26
26a Leavesregularly3-7(-9)-veined, (1.5-)2.0-6.0 mmwide;spikes9-17 mm long .27
26b Leavesregularly3-veined,rarelysome 5-veined,mostly0.3-2.0 mm wide;spikes3-11(-13) mm long
...........................................................................
28
27a Stipulessplit into two remnants,fusedat base, almostentirelyfree at apex;leavesdistinctlymucronate
at the apex,with a faintmarginalvein, 1.5-3.5 mm wide;flowers4-8 in spike;fruits2.4-3.0 mm long
47. P friesii
....................................................................
27b Stipulesnot split into two remnants,convolute(fused on the side towardsto the leaf and free on the
oppositeside); leaves acute at apex, with marginalstrandsstronger,remainingas fibres,(2-)3-6 mm
wide;flowers5-12 in spike;fruits4.3-4.6 mm long.49.
P gayi
28a Leaf midriboccupying 1/3-3/5 of the leaf width nearthe base, with stronglyconvex lower side in
cross-section,not borderedby rows of lacunae;flowerswith 1(-3) carpels;leaves mostly0.3-1.0 mm
wide.55.
P trichoides
28b Leaf midriboccupyingup to 1/5 of the leaf widthnearthe base, with slightlyconvex lower side in
cross-section,mostlyborderedby rowsof lacunae;flowerswith4(-5) carpels;leaves0.5-2.5(-3. 1) mm
wide.29
29a Fruitswith a dorsalkeel up to 0.4 mm high,often with 2 lateralkeels;spikes2-7 mm long in fruit...
. ........................
...........................................................................
29b Fruitswithdorsalside rounded,lateralkeels alwaysabsent;spikes3-14 mm long in fruit....
.... 31
30a Fruitsconvex on sides, 2.3-4.0 mm long, 3-keeled;dorsalkeel ridge-like,to 0.2 mm high;peduncles
6-14 mm long ..........................................................
53. P hillii
30b Fruitsconcaveon sides, 1.4-2.7 mmlong, 1-keeled;dorsalkeel wing-likeandundulate,to 0.4 mmhigh;
52. P.foliosus
pedunclesmostly 3-11 mm long..........................................
31a Stipulesdelicate, not fibrous,greenish,brownor greenishwhite, translucentwhen dry, connateor
convolute;leaves flaccid,acuteor acuminateat apex,not finely pointed.....
....... 48. P pusillus
31b Stipules(especiallythose of turions)firm,coarselyfibrous,whitish,opaquewhendry,connate;leaves
rigid,graduallytaperingto a fine, almostbristle-likepoint,or sometimesacuteat apex .....
...... 32
32a Leaves0.5-1.1 mm wide; spikes3-10 mm long;flowerwhorlscontiguous...........
50. P rutilus
32b Leaves0.6-2.0 mm wide;spikes6-13 mmlong;flowerwhorlsremote.....
....... 51. P strictifolius
252
G. Wiegleb & Z. Kaplan
33a (14) Submergedleaves narrowlylinear,0.1-1 .0(-l .9) mm wide; laminaof floatingleaves 3-11 mm
wide.
............................................................
34
33b Submergedleaves broadlylinearor ribbon-liketo broadlyovate,morethan2.5 mm wide, or phyllodial,
0.2-3.5 mm wide; laminaof floatingleaves, if present,morethan(7-) 1 mm wide .....
........ 36
34a Fruitswithdorsalkeel stronglydevelopedandcristate,beakconspicuous.....
........ 57. P. cristatus
34b Fruitswith dorsalkeel entireor obtuselydentate,beakshort..............................
35
35a Beak in ripe fruitsstraight;submergedleaves 0.5-1.2(-1.9) mm wide, 30-75 times as long as wide;
floatingleaves acuteat apex, with petioles0.2-1.1 times as long as the lamina..... 56. P. octandrus
35b Beak in ripe fruits slightly recurved;submergedleaves 0.1-0.5 mm wide, 150-250 times as long as
wide;floatingleaves obtuseat apex,withpetioles0.7-2.0 timesas long as the lamina.... 58. P. vaseyi
36a All submergedleaves consistingof narrowlylinearphyllodes,with a convex lower side, 0.2-3.5 mm
wide, 70-300 timesas long as wide, lateralveins inconspicuous;floatingleaves almostalwayspresent,
with laminaoblong to broadlyellipticalor broadlyovate;endodermisof U-type;interlacunar
bundles
alwayspresent........
37
36b Mostor all submergedleaves withwell developedlamina,flaton bothsides, 1-80 mmwide,2-70 times
as long as wide, lateralveins conspicuous;floatingleaves absentor present,with laminaof various
shape;endodermismostlyof 0-type, sometimesof U-type;interlacunar
bundlespresentor absent. . 38
37a Laminaof floating leaves 40-100(-140) mm long, (7-)20-45(-80) mm wide, 17-25(-35)-veined,
usually subcordateat the base; submergedleaves 0.8-3.5 mm wide; fruits 3.8-5.0 mm long;
pseudohypodermis
presentin 1-2 layers............
16. P. natans
................
37b Laminaof floatingleaves(13-)22-40(-55) mmlong,(5-)10-22(-29) mmwide,(7-)9-19(-23)-veined,
cuneateto roundedat the base; submergedleaves 0.2-1.0 mm wide; fruits 2.5-3.5(-3.7) mm long;
pseudohypodermis
absent,rarelypresentin I layer..........
17. P oakesianus
..............
38a Submergedleaves with relativelybroadrows of lacunaeborderingthe midrib,linearto ribbon-like,
delicate,flaccid, 1-1 mm wide, 14-70 times as long as wide, sessile except for the uppermostones .
................................................................
39
38b Submergedleaves with relativelynarrowrows of lacunaeor completelywithoutlacunae,lanceolateor
narrowlyellipticalto broadlyovate(lanceolateto ribbon-likein P.solomonensis),membranous,
(2-)4-75
mm wide, 1.3-19.0(-21.0) times as long as wide, sessile or petiolate......
41
.................
39a Laminaof floatingleaves 14-31 mm long,6-9 mm wide,5-9-veined;submergedleaves 1-4 mm wide,
3-7-veined;inflorescencesregularlyinsertedintheaxilsof bothfloatingandsubmergedleaves;peduncles
11-27 mm long .........
30. P ulei
39b Laminaof floatingleaves33-80 mmlong,7-25 mmwide,9-21-veined;submergedleavesusually3-11
mm wide, 5-9(-13)-veined; inflorescencesinsertedmostly in the axils of floatingleaves; peduncles
23-lO0 mm long ............
40
40a Petiolesof truefloatingleaves not flattened,20-60(-90) mm long; submergedleaves persistent.
..................................................................
29. P epihydrus
40b Petiolesof floatingleaves flattened,40-115(-150) mm long; submergedleaves mostlydecayingearly
31. P montevidensis
..............................................................
41a Submergedleaves sessile, amplexicaulto semiamplexicaulat base, claspingthe stem;floatingleaves
alwaysabsent. ................................................................
42
41b Submergedleaves petiolateor sessile with cuneatebase, not claspingthe stem;floatingleaves present
or absent....................................................................
44
42a Leavesentireat margins,distinctlyhoodedat apex,60-360 mm long;fruits4.5-5.5 mm long; stele of
prototype;endodermisof U-type,rarelyO-type;interlacunarbundles
present,strong... 28. P praelongus
42b Leavesdenticulateat margins,notor onlyscarcelyhoodedat apex,mostly15-80 mmlong;fruits2.2-4.2
mm long; stele of specializedtriotype;endodermisof 0-type; interlacunar
bundlesabsent.......
43
Taxonomy of Potamogeton
253
........ 26. P.perfoliatus
43a Stipulesdelicate,withoutfibres,decayingearly;fruits2.2-3.5 mmlong .....
............. 27. P richardsonii
43b Stipulesfibrous,persistingas fibres;fruits2.7-4.2 mm long .....
44a All truesubmergedleaves sessile or sometimesveryshortlypetiolate,withpetiolesless than5 mmlong,
leavesmayhavemuch
0.00-0.05 timesas long as the lamina,the uppermostsubmergedor intermediate
45
....................................
longerpetioles ...............
44b Mostorall submergedleavespetiolate,withmostorall petiolesatleast(3-)5 mmlong,(0.03-)0.05-5.00
49
timesas long as the lamina.......
45a Submergedleavesobtuseto narrowlyobtuseandslightlyhoodedatapex,9-15-veined;stemunbranched;
petiolesof floatingleaves0.1-0.8 timesas long as the lamina;bothsubmergedandfloatingleaves with
bundlesabsent............
a strongreddishto brownishtinge, especiallywhendried;interlacunar
13. P alpinus
..................................................................
45b Submergedleaves acute to mucronateand flat at apex, usually 3-11-veined (up to 17-veinedin
P illinoensis);stem unbranchedto richlybranched;petiolesof floatingleaves mostly0.8-4.0 timesas
bundlespresent
long as the lamina;leaves greenor rarelyonly witha slightbrownishtinge;interlacunar
or absent.46
orsparinglybranched
46a Submergedleavesdenticulateatmargins;stemusuallyrichlybranched(unbranched
in P illinoensis);pedunclesas thick as or up to muchthickerthanthe stem;fruits2.4-3.9 mm long;
stele of protoor trio to oblongtype;endodermisof U-type.47
46b Submergedleaves entireat margins;stemunbranchedor sparinglybranched;pedunclesas thickas the
stem;fruits 1.7-2.6 mm long; stele of four bundlestype, rarelyof protoor trio type; endodermisof
0-type .48
47a Submergedleaveslinear-oblongto oblongor oblanceolate,mostly5-12 mm wide;stipulesusually6-25
25. P gramineus
mm long;fruits2.4-3.1 mm long ..........
47b Submergedleaves narrowlylanceolateor oblongto elliptical,mostly 12-53 mm wide; stipules20-80
mm long;fruits2.7-3.9 mm long.53
to narrowlyelliptical;fruitingspikes 10-25 mm long,6-7
48a Submergedleaves narrowlylinear-lanceolate
mm wide; fruits 2.0-2.6 mm long; stipulesusually 25-35 mm long; subepidermalbundlespresent,
33. P cheesemanii
mostlystronglydeveloped...........
48b Submergedleavesnarrowlyoblongto broadlyovate;fruitingspikes7-22 mmlong,? 5 mmwide;fruits
bundlesabsent....... 32. P drummondii
1.7-2.0(-2.5) mmlong;stipules16-25 mmlong;subepidermal
49a (44) Laminaof submergedleaves sometimessagittateat base, 105-160 mm long; petiolesof floating
leaves 115-185 mm long; peduncles considerablythicker than the stem, 130-180 mm long;
18. P papuanicus
absent..........
pseudohypodermis
49b Laminaof submergedleaves cuneateto cordateat base, neversagittate,30-310 mm long; petiolesof
floatingleaves5-260(-390) mm long;pedunclesas thickas or thickerthanthe stem, 10-350 mm long;
50
absentor mostlypresent...........................................
pseudohypodermis
50a Maturesubmergedleaves mucronateat the apex,denticulateat margins(at least in young leaves),near
the base of the stem often partlyreducedto phyllodes;petiolesof submergedleaves (0-)2-70(-140)
mm long; interlacunar
bundlesalwayswell developed;endodermisof U-type,exceptionallyof 0-type
51
..........
................................................................
50b Submergedleaveseitherobtuseor acuteat the apex,entireor minutelydenticulateat margins,phyllodes
nearthe base of the stem almostalwaysabsent;petiolesof submergedleaves 1-200(-250) mm long;
54
interlacunar
bundlespresentor absent;endodermisof 0-type, exceptionallyof U-type ...........
51a Petiolesof submergedleaves 30-70(-140) mm long;submergedleaves oblong,with parallelmargins;
fruits2.0-3.3 mm long;pedunclesslightlythickerthanthe stem;stele of triotype, rarelyof prototype
2 1. P wrightii
..................................................................
51b Petiolesof submergedleavesusually(0-)2-40 mmlong;submergedleavesellipticalor lanceolate,with
convex margins;fruits 2.7-4.5 mm long; pedunclesdistinctlythickerthan the stem; stele mostly of
52
oblongtype in typicalshoots.....................................................
254
G. Wiegleb & Z. Kaplan
52a Submergedleavesmostlyelliptical,25-65 mmwide,conspicuouslydenticulate;petiolelengthrelatively
constant,rangingbetween2-7(-15) mm;floatingleaves alwaysabsent;stele mostlyof oblongtype . .
24. P lucens
.......................................
..............................
52b Submergedleaves narrowlylanceolateto elliptical,mostly5-40 mm wide, often only inconspicuously
denticulate;petiole length variable,rangingbetween0-40(-65) nmm
long; floatingleaves presentor
absent;stele morevariable,rangingfromprototo oblongtype.53
53a Submergedleaves mostly 15-40 mm wide, 9-17-veined, mostly4-6 times as long as wide;laminaof
floatingleaves mostly25-65 mm wide .........
22. P illinoensis
.................
53b Submergedleaves (3-)7-28 mm wide, 7-11-veined, mostly 6-17 times as long as wide; laminaof
floatingleaves 12-30 mm wide .......
23. P schweinfurthii
.................
54a (50) Stem conspicuouslyblack-spotted;submergedleaves undulatealong the margins;interlacunar
bundlesabsent........................
7. P pulcher
54b Stemnot conspicuouslyblack-spotted,sometimesreddish-spotted
or mostlywithoutconspicuousspots;
submergedleaves ? flat alongthe margins(undulatein P australiensis);interlacunar
bundlesabsentor
present........................
55
55a Floatingleaves translucent,membranous,with conspicuoussecondaryveins; fruits 1.3-2.5 mm long;
petioles of floatingleaves 5-50 mm long; interlacunar
bundlesabsent;subepidermalbundlesalways
present;pseudohypodermis
56
present......................
55b Floatingleaves opaque,coriaceous,with inconspicuoussecondaryveins (in P tepperisecondaryveins
conspicuous);fruits 1.8-5.2(-5.7) mm long; petioles of floating leaves 20-260(-390) mm long;
interlacunar
bundlesabsentormostlypresent;subepidermal
bundlespresentorabsent;pseudohypodermis
presentor absent........................
57
56a Fruits1.3-1.9 mm long; laminaof floatingleaves 13-21-veined,2-10 times as long as the petiole;
pedunclesnot thickerthanstem .....................
3. P coloratus
56b Fruits2.0-2.5 mm long; laminaof floatingleaves 9-15-veined, 0.5-5.0 times as long as the petiole;
pedunclesthickerthanstem................................4.
P australiensis
57a Whole plants strongly reddish brown, especially when dried; submergedleaves decaying early;
pseudohypodermis
1. P. ferrugineus
alwayspresent................................
57b Plantspalegreento olive-green,locallyalso witha brownishtinge;submergedleavesdecayingor mostly
absentor present..............................
persistent;pseudohypodermis
58
58a Submerged leaves (21-)25-37(-41)-veined, with petioles (2-)6-80 mm long; floating leaves
(21-)25-5 1-veined,oftencordateto roundedat base....................................
59
58b Submergedleaves 3-21-veined, withpetiolesmostly30-250 mm long (in P solomonensisandP fryeri
only (1-)5-50 mm long); floatingleaves 9-25-veined (up to 35-veinedin P fryeri), mostlycuneate,
sometimesalso roundedto subcordateat base................................
60
59a Submergedleaves (at least the uppermost)foldedand stronglyarcuate;fruits3.9-5.2(-5.7) mm long,
not tricarinate,with an indistinct,smooth dorsal keel only; stem indistinctlysclerenchymatous;
pseudohypodermis
P. amplifolius
present................10.
59b Submergedleaves ? flat; fruits(2.7-)3.0-4.1 mm long, distinctlytricarinate,with stronglysculptured
dorsalandlateralkeels;stemstronglysclerenchymatous,
withpersistentfibresvisibleto the nakedeye;
absent.............................6.
pseudohypodermis
P sulcatus
60a Unrolledstipules6-15 mm wide,withhyalinemargins,persistent;submergedleavesellipticalto oblong
or lanceolate,mostly 1.6-2.8 times as long as wide, obtuse at apex; petioles of submergedleaves
(2-)10-35 mm long; laminaof floatingleaves ovate or ellipticalto obovate,1.6-2.8 times as long as
wide;petioleof floatingleavesalmostalwayswitha discolouredsectionat thejunctionwiththelamina;
pseudohypodermis
presentin 2-3(-4) layers..............................
9. P linguatus
60b Unrolledstipulesmostly3-10 mmwide,withouthyalinemargins,persistenttodecayingearly;submerged
leaves lanceolateor ribbon-liketo narrowlyoblongor oblong,mostly2.3-19.0 times as long as wide,
acuteto narrowlyobtuseatapex;petiolesof submergedleavesmostly25-250 mmlong(inP solomonensis
Taxonomy of Potamogeton
255
and P. fryeri only (1-)5-50 mm long); laminaof floatingleaves narrowlyellipticalto lanceolateor
linear-oblong,1.5-6.0 timesas longas wide;petioleof floatingleaveswithormostlywithouta discoloured
sectionat thejunctionwiththe lamina;pseudohypodermis
absentor presentin 1(-2) layers...... . 61
61a Laminaof submergedleaves lanceolateto ribbon-like,5-8(-15) mmwide, 8-19 timesas long as wide;
floatingleaves 9-11-veined; spikesdimorphic,cylindricalor subglobose;stele of reducedtrio or four
bundlestype .........................................................
34. P. solomonensis
61b Lamina of submerged leaves narrowly oblong or oblong to lanceolate, (5-)8-38 mm wide,
(1.9-)2.3-11.0(-15.0) times as long as wide; floating leaves 11-35-veined; spikes monomorphic,
cylindrical;stele of protoor triotype ..
.............................................
62
62a Petioleof floatinganduppermostsubmergedleaves oftenflattenedandwinged,withundulatemargins;
laminaof floatingleaves 21-35-veined;lower submergedleaves sessile to subsessile,the upperones
petiolate,the petioles0-40 mm long, 0.0-0.3 timesas long as the lamina;peduncles70-150 mm long;
fruits4.5-5.0 mm long;interlacunar
bundlespresent.......
8. P.fryeri
........................
62b Petiole of both floating and submergedleaves terete;lamina of floating leaves 11-25-veined; all
submergedleaves (long) petiolate,the petioles (12-)30-250 mm long, (0.2-)0.5-5.0 times as long as
the lamina;pedunclesmostly25-120 mm long;fruits1.8-4.8 mm long;interlacunar
bundlespresentor
mostlyabsent.............................................................
63
63a Fruits2.7-4.8 mm long; submergedleaves (5-)9-21-veined, minutelydenticulateor entireat margins,
with petioles30-250 mm long;endodermisof 0-type or U-type ........
...................
64
63b Fruits1.8-2.6 mm long (up to 3.0 mm long in P tepperi);submergedleaves (3-)5-15-veined, entireat
margins,withpetiolesmostly 15-90 mm long;endodermisof 0-type ......
.................
67
64a Flowerswith 1-2(-3) carpels;petiolesof floatingleaves(50-)80-260(-390) mmlong.. 19.P distinctus
64b Flowerswith (3-)4(-5) carpels;petiolesof floatingleaves 18-210(-280) mm long.65
65a Submergedleavespersistent,(1 -)22-38 mmwide;floatingleavesmostly60-130 mmlong;interlacunar
bundlesabsent,rarelya few present;endodermismostlyof 0-type, rarelyof O-U-type... 20. P.nodosus
65b Submergedleaves decayingearly,6-27 mm wide;floatingleavesmostly30-80 mm long;interlacunar
bundlespresent;endodermisof U-type,rarelyof 0-type .................................
66
66a Petiolesof floatingleaves 18-110(-195) mm long, 0.3-3.0 times as long as the lamina;laminamostly
20-41 mm wide; stele of trio type; interlacunar
bundlespresentin 2-3 circles;subepidermalbundles
present..
14. P thunbergii
66b Petiolesof floatingleaves usually75-170(-280) mm long, 1.8-6.0 times as long as the lamina;lamina
7-26 mm wide;stele of protoor triotype;interlacunar
bundlespresentin 1 circle;subepidermal
bundles
absentor a few present..............15.
P parmatus
67a (63) Submergedleavesdecayingearly,5-9(-1 1)-veined;peduncles0.8-3.0 timesas long as thefruiting
spike,slightlythinnerthanthestem;steleof triotype;interlacunar
bundlespresent.... 12.P.stenostachys
67b Submergedleaves persistentor decaying,(3-)5-17-veined; peduncles2.5-6.0 times as long as the
fruitingspike,as thickas the stem;stele of prototo triotype;interlacunar
bundlesabsent....
.... 68
68a Submergedleaves decayingearly,linear-lanceolate
to ovate-lanceolate;
fruits(2.0-)2.5-3.0 mm long;
bundlesabsent...... 5. P. tepperi
floatingleaves 15-23-veined;stele of prototo triotype;subepidermal
68b Submergedleaves persistent,linear-oblongto oblong or narrowlyelliptical;fruits 1.8-2.6 mm long;
floating leaves mostly 11-19-veined (up to 25-veined in P. polygonifolius);stele of proto type;
bundlespresent.....................................................
subepidermal
69
69a Submergedleaves5-15 timesas longas wide;fruits1.9-2.6 mm long..............
69b Submergedleaves 1.9-5.0 timesas longas wide;fruits1.8-2.3 mmlong.2.
1. P.polygonifolius
P suboblongus
256
G. Wiegleb & Z. Kaplan
AN ACCOUNT OF THE SPECIES
1. Potamogeton polygonifolius POURRET,
Mem. Acad. Sci. Toulouse 3: 325. 1788.
P natans subsp. polygonifolius (POURR.)HOOK.f., Stud. Fl. Brit. Isl. 370. 1870.
P. natans var. y polygonifolius (POURR.)FIORI,Fl. Anal. Ital. 1: 154. 1896.
- P. oblongus VIv., Ann. Bot. 1(2): 102. 1804. ("oblongum")
- P. affinis BOENN.ex CHAM.et SCHLTDL.,
Linnaea 2(2): 216. 1827, pro syn. ("affine")
-P paludosus BORYex CHAM.et SCHLTDL.,
Linnaea 2(2): 216. 1827, pro syn. ("paludosum")
P microcarpus BOISS.et REUT.,Diagn. P1. Nov. Hisp. 24. 1842.
P. polygonifoliussubsp.microcarpus(Boiss. et REUT.)NYMAN,
Consp.Fl. Eur.4: 681. 1882.
P. polygonifoliusvar.microcarpus(Boiss. et REUT.)A. BENN.,Ann. K. K. Naturhist.Hofmus.Wien7:
287. 1892.
- P polygonifolius
var.PpseudofluitansSYME,Engl. Bot. ed. 3. 9: 28. 1869. ("pseudo-fluitans")
- P polygonifoliussubsp.pseudofluitans(SYME)MAGNIN,
Bull. Soc. Bot. France43: 437. 1896.
-P cyprifoliusLOWE
ex GRAEBN.
in ENGL.,Pflanzenr.31 (IV.11): 65. 1907,pro syn.
- P scheelei G. PREUSSex GRAEBN.in ENGL.,Pflanzenr. 31 (IV.11): 67. 1907, pro syn. ("Scheelei")
= P. anglicus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 180. 1916, pro hybr. P coloratus x
P. polygonifolius.
Description
Rhizomefiliformto slender,terete,perennial,sometimeswithapicalscalyturions.Stemunbranched
orspanrngly
branched,filiformto slender,terete,annualto perennial,wintergreen,continuingto grow afterflowering;
specializeddormantturionsnotdeveloping.Submergedleavesusuallypresent,absentin landformsandshallow
waterforms,petiolate;laminalinear-oblongto narrowlyelliptical,50-130(-220) mm long, 3-25(-55) mm
wide, 5-15 times as long as wide, yellow-greento brightgreen,often with a reddishtinge, (3-)5-15-veined,
withnarrowrowsof lacunaeborderingthe midrib,entireat margins,cuneateat base,narrowlyobtuseat apex;
petiole 15-80(-240) mm long, 0.5-5.0 times as long as the lamina.Intermediateleaves sometimespresent,
petiolate,oblong.Floatingleaves petiolate;laminaoblongor ellipticalto ovate, (10-)25-75(-105) mm long,
(5-)10-65 mm wide, 1.5-4.0 timesas long as wide, opaque,coriaceous,brightgreento brownishgreen,often
with a reddishtinge, 11-19(-25)-veined, cuneateto roundedor subcordateat base, acuteto obtuseat apex;
petiole(13-)25-150(-300) mm long, 0.5-6.0 timesas long as the lamina.Stipulesaxillary,convolute,10-65
mmlong,translucent,
persistent.Peduncles25-100(-185) mmlong,2.5-5.0 timesas longas thefruitingspike,
as thick as the stem, insertedin the axils of floatingleaves. Spikes cylindrical,10-42 mm long in fruit,
contiguous.Flowersnumerous,with 4 carpels.Fruits1.9-2.6 mm long, dorsalkeel indistinct.
Stem anatomy
Stele of proto type, endodermismostly of 0-type, sometimes O-U-type, interlacunarbundles absent,
subepidermal
bundlespresent,pseudohypodermis
present,1-2-layered.
Distribution
W, N, C andS Europe,the Azores,Madeira,N Africa,E NorthAmerica.
Hybrids
13 x 1. P.xspathulatusSCHRAD.
ex W.D.J.KOCH
etZ;z,Cat.PI.Palatinat.5:18.1814, prosp. ("spathulatum")
[= P alpinusx P polygonifolius]
= P kochii EW. SCHULTZ,
Arch. Fl. France Allem. 1: 61 et 72. 1844, nom. illeg. ("Kochii")
= P oblongo-rufescens F.W. SCHULTZ,
Flora 32(15): 230. 1849, nom. illeg.
- P rufescenti-natans F.W. SCHULTZ,Archives de Flore 1(4): 55. 1855, nom. illeg.
- P alpino-natansF.W. SCHULTZ,Jahresber.
Pollichia20-21: 228. 1863, nom. illeg.
P alpinus subsp.spathulatus (SCHRAD.ex W.D.J. KOCHet Zlz) MAGNIN,Bull. Soc. Bot. France 43: 441.
1896.
16 x 1. P. xgessnacensis G. FIsCH.,Mitt.Bayer. Bot. Ges. 1(37):472. 1905. ("Gel3snacensis")
[= P natansx P polygonifolius]
25 x 1. P. xianceolatifolius(TISELIUS)
C.D. PRESTON,
Watsonia 16: 437. 1987.
[= P gramineusx P polygonifolius]
Taxonomy of Potamogeton
257
P. gramineus f. lanceolatifolius TISELIUS,Potamog. Suec. Exs., fasc. 3: [sched.] no. 139, notulae p. 6.
1897.
P gramineus proles heterophyllus var. stagnalis subvar. lanceolatifolius (TISELIUS)GRAEBN.in ENGL.,
Pflanzenr. 31 (IV.II): 88. 1907.
_ P. xseemenii nothof. lanceolatifolius (TISELIUs)HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5):
231. 1916. ("form")
1 x 48. P. xrivularis GILLOT
in MAGNIER,
Scrin. Fl. Select. 6: 118. 1887
[= P polygonifolius x P pusillus]
P lanceolatus var. rivularis (GILLOT)FRYER,J. Bot. 32: 338. 1894.
P lanceolatus subsp. rivularis (GILLOT)MAGNIN,Bull. Soc. Bot. France 43: 441. 1896.
= P xmiguelensis DANDY,Bol. Soc. Brot., ser. 2, 44: 5. 1970.
Notes
(1) P polygonifolius is closely related to P coloratus and P suboblongus.
(2) The assumed eastward distribution of P. polygonifolius in Asia can be attributed to confusion with P
distinctus. The assumed Southern Hemisphere distribution is due to confusion with southern species like P
suboblongus, P cheesemanii, P parmatus, and P stenostachys. The occurrence in these areas has not yet been
proved.
2. Potamogeton
suboblongus
1916
HAGSTROM,Kungi. Svenska Vetenskapsakad. Handl. 55(5): 182.
Description
Rhizome slender, terete, perennial, continously growing, turions or winterbuds not seen. Stem unbranched or
rarely sparingly branched, slender, terete, perennial, not much differentiated from the horizontal shoot;
specialized dormant turions not developing. Differentiation of submerged and floating leaves indistinct.
Submerged leaves, if present, petiolate; lamina subcoriaceous, narrowly elliptical to oblong, 30-90 mm long,
8-17(-38) mm wide, 1.9-5.0 times as long as wide, yellow-green to bright green, sometimes with a reddish
tinge, 7-15-veined, with narrow rows of lacunae bordering the midrib, entire at margins, cuneate at base,
narrowly obtuse at apex; petiole 20-60 mm long, 1.2-1.8 times as long as the lamina. Floating leaves petiolate;
lamina oblong to broadly elliptical or ovate, (20-)30-60(-75) mm long, 8-35 mm wide, 1.6-4.0 times as long
as wide, opaque, coriaceous, bright green to brownish green, Il-15(-21)-veined, cuneate to truncate or
subcordate at base, subacute to rounded at apex; petiole 18-55 mm long, 0.6-1.8 times as long as the lamina.
Stipules axillary, convolute, 9-35 mm long, conspicuous, persistent or partly decaying. Peduncles (34-)45-130
mm long, 2.5-4.0(-5.5) times as long as the fruiting spike, as thick as the stem, mostly terminal in the axils
of floating leaves. Spikes cylindrical, 10-30 mm long in fruit, contiguous. Flowers numerous, with 4 carpels.
Fruits 1.8-2.3 mm long, dorsal keel indistinct.
Stem anatomy
Stele of proto type, rarely reduced to trio (2) type or complex four bundles type, endodermis of 0-type,
interlacunarbundles absent, subepidermal bundles present, in one incomplete ring, pseudohypodermis present,
1-layered.
Distribution
New Zealand, Tasmania?
Note
(1) P. suboblongus is a distinct species of the flora of New Zealand. It is closely related to P polygonifolius
from the Northern Hemisphere.
3. Potamogeton
coloratus
HORNEMANN,Fl. Dan. 9(25): 2, tab. 1449. 1813. ("Coloratum")
_ P hornemannii G. MEY.,Chloris Han. 521. 1836, nom. illeg. ("Hornemanni")
_ P natans var. 6. coloratus (HORNEM.)FIORI,Fl. Anal. Ital. 1: 154. 1896.
= P plantagineus DUCROSex ROEM.et SCHULT',Syst. Veg. ed. 16. 3: 504. 1818.
- P natans subsp. plantagineus (DUCROSex RotM. et SCHULT.)HOOK.f., Stud. Fl. Brit. Isl. 371. 1870.
= P helodes DUMORT.,Fl. Belg. 163. 1827.
-
P siculus TINEOex Guss., Fl. Sicul. Syn. 2(2): 790. 1845, nom. illeg., non J. PRESL1821.
258
G. Wiegleb & Z. Kaplan
= P subflavusH. LORETet BARRANDON,Fl. Montpellier2: 671. 1876.
P. alpinus subsp.subflavus(H. LORETet BARRANDON)GRAEBN.in ENGL.,Pflanzenr.31 (IV.11): 74.
1907.
-P coloratus f. subflavus (H. LORETet BARRANDON)
HAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.
55(5): 179. 1916.
Description
Rhizomeslender,terete,perennial,overwintering
withshortleafy shoots,rarelywithapicalscalyturions.Stem
unbranched
or very sparinglybranched,terete,annual;specializeddormantturionsnot developing.Submerged
leaves petiolate or sometimes subsessile; lamina narrowlyelliptical to oblong, (27-)70-175 mm long,
11-44(-65) mm wide, (2.0-)3.5-8.5 times as long as wide, brightgreen, sometimeswith a reddishtinge,
9-17-veined, with narrowrows of lacunaeborderingthe midrib,entireat margins,cuneateat base, acuteat
apex;petiole (3-)15-65 mm long, 0.05-0.40 times as long as the lamina.Floatingleaves presentor rarely
absent,shortlypetiolate;laminabroadlyellipticalor broadlyovate to suborbicular,(15-)25-85 mm long,
15-55 mm wide, 1.1-2.0 timesas long as wide,translucent,membranous
to subcoriaceous,brightgreen,often
with a reddishor brownishtinge, 13-21-veined,truncateto cordateat base, acuteto obtuseat apex;petiole
5-45 mm long, 0.1-0.5 times as long as the lamina.Stipulesaxillary,convolute,20-65 mm long, translucent,
persistent.Peduncles(18-)30-180 mm long, 1.3-4.0(-6.1) times as long as the fruitingspike,as thickas the
stem.Spikescylindrical,14-45 mm long in fruit,contiguous.Flowersnumerous,with4 carpels.Fruits1.3-1.9
mm long, dorsalkeel indistinct.
Stem anatomy
Steleof prototype,distinctlylobed,endodernmis
mostlyof 0-type, rarelyO-U-type,interlacunar
bundlesmostly
absent,subepidermal
bundlespresent,pseudohypodermis
usuallypresent,1-2-layered.
Distribution
W, C and S Europe,N Africa,SW Asia (Turkey).
Hybrids
3 x 25. P. xbillupsiiFRYER,
J. Bot. 31: 353, t. 337 et 338. 1893. ("Billupsii")
[= P coloratus x P gramineus]
3 x 48. P. xianceolatus SM. in SOWERBY,
ENGL.Bot. 28: t. 1985. 1809, pro sp. ("lanceolatum")
[= P coloratus x P pusillus]
= P lanceolatus var. hibernicus A. BENN.in PRAEGER,Irish Naturalist 5: 243. 1896.
- P perpygmaeus HAGSTR.ex DRUCE,Bot. Soc. Exch. Club Brit. Isles 6 (1922): 630. 1923, nom. nud.
P xperpygmaeus HAGSTR.ex DRUCE,List Brit. P1. ed 2. 116. 1928.
4. Potamogeton australiensis A. BENNETr,
J. Bot. 48: 149. 1910.
= ? P. membranaceus HAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5): 157. 1916.
Description
Rhizomeslender,terete,perennial,turionsor winterbudsnot seen. Stem unbranchedor sparinglybranched,
slenderto robust,terete,annual;specializeddormantturionsnot developing.Submergedleaves petiolateto
subsessile;laminanarrowlyellipticalto lanceolate,30-50(-90) mm long, 8-24 mm wide, 2-4 timesas long
as wide, brightgreen,7-13-veined, with narrowrows of lacunaeborderingthe midrib,entirebut becoming
undulateat marginswhen dried,cuneateor truncateat base, subacuteat apex;petiole (2-)10-15(-40) mm
long,0.05-0.50 timesas long as the lamina.Floatingleavespresentorabsent,shortlypetiolate;laminabroadly
ellipticalto ovate, 15-35 mm long, 12-16 mm wide, 1.2-3.0 timesas long as wide, translucent,membranous,
brightgreen,9-15-veined, truncateor subcordateat base,roundedat theapex;petiole10-50 mm long,0.2-1.2
times as long as the lamina.Stipulesaxillary,convolute,15-26 mm long, translucent,persistent.Peduncles
55-95 mm long, 2.5-6.0 times as long as the fruitingspike,usuallythickerthanthe stem,insertedin the axils
of submergedor rarely floating leaves. Spikes cylindrical,15-25 mm long in fruit, contiguous.Flowers
numerous,with 4 carpels.Fruits2.0-2.5 mm long, dorsalkeel indistinct.
Stem anatomy
Stele of protoor trio (1) type, lobed, endodermisof 0-type, interlacunar
bundlesabsentor scatteredones
presentin the outercircle, subepidermalbundlespresent,pseudohypodermis
present,1-3-layered.
Taxonomy of Potamogeton
259
Distribution
Tasmania, SE Australia (exact distribution unknown).
Note
(1) P australiensis is a distinct species of the flora of Tasmania and Australia. The exact delimitation is still
unclear, as confusion with P. cheesemanii, P sulcatus, and P suboblongus has occurred. The present description
is based on the authentic specimens collected by Wilson from Merrigang Creek, Victoria, sent by Maiden to
A. Bennett and preserved at BM. Only one recent specimen (Morris 258 713, Tasmania, OLD) is included. In
their treatment of Potamogeton submitted to Flora of Australia, Papassotiriou, Jacobs and Hellquist include
also a form with true floating leaves into their concept of P. australiensis which has not yet been described in
the literature.These plants have roundish floating leaves up to 65 mm in length, 55 mm in width and 32 veins.
As they also differ in some other characters from the plants known so far (e.g. the larger fruits) they are not
included in the present treatment. Cultivation experiments are necessary to test the identity of the divergent
morphotypes.
5. Potamogeton
tepperi A. BENNETT,J. Bot. 25: 178. 1887. ("Tepperi")
- P. tricarinatus F. MUELL.ex A. BENN.,J. Bot. 25: 177. 1887, nom. nud.
Description
Rhizome slender, terete, perennial, winterbuds not seen. Stem unbranched, slender, terete, annual; winterbuds
as axillary leafy shoots, specialized dormant turions not developing. Submerged leaves petiolate, decaying
early; lamina linear-lanceolate to ovate-lanceolate, 40-60(-104) mm long, 10-20 mm wide, 2.5-6.0 times as
long as wide, pale green, 11-15-veined, with narrow bands of lacunae bordering the midrib, entire at margins,
cuneate at base, subacute at apex; petiole 32-65 mm long, 0.5-1.5 times as long as the lamina. Intermediate
leaves sometimes present, petiolate. Floating leaves present, petiolate; lamina ovate-lanceolate to ovate,
40-60(-80) mm long, 20-30(-40) mm wide, 1.5-2.5 times as long as wide, coriaceous, bright green,
15-23-veined, with conspicuous secondary veins, subcordate at base, rounded to subacute at apex; petiole
40-80(-100) mm long, 0.8-1.5 times as long as the lamina. Stipules axillary, convolute, 25-40 mm long,
decaying early. Peduncle 40-75(-90) mm long, 2.0-6.0 times as long as the fruiting spike, as thick as the
stem, inserted in the axils of floating leaves. Spike cylindrical, 15-35 mm long in fruit, contiguous. Flowers
12 to numerous, with 4 carpels. Fruits (2.0-)2.5-3.0 mm long, dorsal and lateralkeels distinct, but not tuberculate.
Stem anatomy
Stele of proto or trio type, endodermis of 0-type, interlacunarbundles absent, subepidermal bundles usually
absent, pseudohypodermis present, 1-layered.
Distribution
E and SE Australia (exact distribution unknown).
Note
(1) At present not enough information is available on the exact delimitation of P tepperi. This taxon is not
identical with the widespread P sulcatus, as it lacks the tricarinate fruits. It is similar to P suboblongus but
differs in the smaller fruit size and the distinct differentiation of submerged and floating leaves. We only
recognize the specimens originally collected by Bailey and similar plants collected later along the east cost of
Australia. Outside Australia, frequent misapplication of the name P tepperi to P nodosus and P distinctus has
occurred, but the taxon is not identical with these species. It is differentiated by the presence of a
pseudohypodermis, the absence of dentation of submerged leaves, and the smaller fruit size. Nevertheless
P nodosus occurs on the Australian continent.
6. Potamogeton
sulcatus
A. BENNETT,Ann. K. K. Naturhist. Hofmus. Wien 7: 294. 1892.
= P muricatus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 165. 1916.
Description
Rhizome slender to robust, terete, perennial, winter buds not seen. Stem unbranched, slender to robust, terete,
annual; specialized dormant turions not developing. Submerged leaves petiolate; lamina oblong-lanceolate to
oblong or elliptical, 50-120(-200) mm long, 10-40(-65) mm wide, 2.2-7.0 times as long as wide, pale green,
27-35 veined, with narrow rows of lacunae bordering the midrib, entire at margins, cuneate to rounded at base,
rounded to subacute at apex; petiole (6-)20-80 mm long, 0.1-0.6 times as long as the lamina. Intermediate
260
G. Wiegleb & Z. Kaplan
leaves sometimes present, petiolate; petiole up to 140 mm long. Floating leaves present or sometimes absent,
petiolate; lamina broadly elliptical to suborbicular, 30-150 mm long, 10-70 mm wide, 1.3-2.7 times as long
as wide, opaque, coriaceous, bright green, 25-35(-39)-veined, cordate at base, rounded at apex; petiole 30-60
mm long, 0.5-2.0 times as long as the lamina. Stipules axillary, convolute, 25-40(-50) mm long, translucent,
decaying or persistent. Peduncles 40-80(-180) mm long, 0.8-2.3 times as long as the fruiting spike, as thick
as or slightly thicker than the stem, inserted in the axils of floating and submerged leaves. Spikes cylidrical,
30-80 mm long in fruit, contiguous. Flowers numerous, with 4 carpels. Fruits (2.7-)3.0-4.1 mm long, dorsal
keel distinct, tuberculate, strong lateral keels distinct.
Stem anatomy
Stele of proto or trio (2) type, with strong sclerenchymatic bundle sheaths and a cambium-like structurebelow
the endodermis, endodermis of 0-type, interlacunar bundles present in 1-3 circles, subepidermal bundles
present or absent, pseudohypodermis absent.
Distribution
E and S Australia.
Note
(1) We choose P sulcatus as the appropriatename of the frequently collected Australian taxon with the fibrous
stem. However, the simple equation "P sulcatus = P tricarinatus" does not hold. P sulcatus seems to be
restricted to E and S Australia (Murray river catchment). For P tricarinatus see below (under P cheesemanii).
7. Potamogeton puicher TuCKERMAN,Amer. J. Sci. Arts, ser. 1, 45: 38. 1843.
= Spirilluspulcher(TUCK.)NIEUWL.,Amer.Midl.Naturalist3: 16. 1913.
P pulcher f. amphibius HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 153. 1916.
Description
Rhizome slender, terete, perennial. Stem unbranched, slender, terete, annual, usually conspicuously
black-spotted especially near the base; specialized dormantturions not developing. Submerged leaves petiolate
to subsessile; lamina long lanceolate or narrowly oblong to oblong, 80-140(-215) mm long, 10-25(-35) mm
wide, 3-10 times as long as wide, yellow-green to bright green, (9-)1 1-21-veined, with narrow rows of lacunae
bordering the midrib, entire and usually strongly undulate at margins, narrowly to broadly cuneate at base,
acute at apex; petiole 1-15(-18) mm long, 0.0 1-0.20 times as long as the lamina. Intermediateleaves sometimes
present. Floating leaves petiolate; lamina broadly oblong or elliptical to broadly ovate, 20-75(-108) mm long,
15-60(-85) mm wide, 1.2-2.5 times as long as wide, opaque, coriaceous, bright green to brownish green,
often with a reddish tinge, (19-)21-29(-41)-veined, rounded to subcordate at base, acute to rounded at apex;
petiole 36-180 mm long, 0.7-2.5 times as long as the lamina, rarely with a discoloured section at the junction
with the lamina. Stipules axillary, convolute, 20-50 mm long, translucent,decaying early to persistent. Peduncles
50-80(-1 10) mm long, 2.0-3.5 times as long as the fruiting spike, as thick as or slightly thinner than the stem.
Spikes cylindrical, 20-45 mm long in fruit, contiguous. Flowers numerous, with 4 carpels. Fruits 3.1-4.1(-4.7)
mm long, dorsal keel distinct.
Stem anatomy
Stele of proto type, endodermis of 0-type, interlacunar bundles absent, subepidermal bundles absent,
pseudohypodermis present, 1-layered.
Distribution
C and E North America.
8. Potamogeton fryeri A. BENNETT,J. Bot. 45: 234. 1907. ("Fryeri")
= P subsessilifolius A. CAMUSin LEcoMTE,Not. Syst. 1: 86. 1909.
- P sessilifolius A. CAMUSin LECOMTE,
Not. Syst. 1: 87. 1909, nom. nud.
= P torquatus KoIDZ., Bot. Mag. (Tokyo) 43: 397. 1929.
Description
Rhizome slender to robust, terete, perennial, of aseasonal growth, with wintergreen shoots; winterbuds not
developing or as non-dormant scaly turions. Stem unbranched or sparingly branched in autumn, slender to
robust, terete, annual or perennial; specialized dormant turions not developing. Submerged leaves usually
present, absent in landforms, lower ones sessile to subsessile, the upper ones petiolate; lamina linear-lanceolate
Taxonomy of Potamogeton
261
to oblong, sometimesthat of the lowest leaves partlyreducedto phyllodes,105-150 mm long, 12-16 mm
wide, 6-11(-14) as long as wide, yellow-greento brightgreen, 5-9-veined, with narrowrows of lacunae
borderingthe midrib,entireat margins,cuneateat base, acuteat apex;petiole0-40 mm long, 0.0-0.3 times
as long as the lamina,mostly flattenedand winged, with undulatemargins.Intermediateleaves sometimes
present,petiolate;petioleup to 115 mm long. Floatingleavesusuallypresent,petiolate;laminalanceolateor
oblanceolateto elliptic,65-120(-150) mmlong, 18-40(-75) mmwide, 1.3-5.5 timesas long as wide,opaque,
coriaceous,brightgreento olive green,21-35-veined, roundedto broadlycuneateat base andnarrowedinto
thepetiole,acuteatapex;petiole(65-)80-2 10mmlong,0.9-2.5 timesas longas thelamina,oftenconspicuously
wingedtowardsthe lamina,rarelywitha discolouredsectionat thejunctionwiththe lamina.Stipulesaxillary,
convolute,(30-)50-100 cm long, opaque,fibrous,whitish,persistent.Peduncles70-150 mm long, 2-6 times
as long as the fruitingspike, as thick as the stem, thinnerdirectlybelow the spike, insertedin the axils of
floatingleaves. Spikes cylindrical,20-30(-50) mm long in fruit,contiguous.Flowersnumerous,with (3-)4
carpels.Fruits4.5-5.0 mm long, dorsalkeel distinct.
Stem anatomy
Stele of proto type, lobed, endodermisof 0-type, interlacunarbundlespresentin 2-3(-4) circles, strong,
multicellular,scatteredsubepidermalbundlespresent,pseudohypodermis
present,1-2-layered.
Distribution
EastAsia (Korea,Japan,RussianFarEast,China?).
9. Potamogeton linguatus HAGSTROM
in DUSEN,Ofvers. Forh. Kongi. Svenska Vetensk.-Akad.
4: 259. 1901.
= ? P montanusC. PRESL,Reliq. Haenk.1(2): 85. 1827.
= P. badioviridis HAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5): 161. 1916.
Description
Rhizomeslenderto robust,terete,perennial,winterbudsnot seen. Stem unbranchedor sparinglybranched,
slenderto robust,tereteor subterete,annual;specializeddormantturionsnot developing.Submergedleaves
shortpetiolateto subsessile;laminaellipticalto oblongor lanceolate,40-60(-1 10) mm long, (5-)15-34 mm
wide, 1.6-2.8(-8.0) as long as wide, yellow-greento brightgreen,13-19-veined,withnarrowrowsof lacunae
borderingthe midrib,entire at margins,cuneateat base, obtuse at the apex; petiole (2-)10-35 mm long,
(0. 1-)0.2-0.7 timesas long as the lamina.Floatingleavespresentor sometimesabsent,petiolate;laminaovate
or ellipticalto obovate,(30-)55-83 mm long, (15-)21-35(-50) mm wide, 1.6-2.5 times as long as wide,
opaque,coriaceous,brightgreento olive green, 11-21-veined,cordateto roundedor broadlycuneateat base,
acute to roundedat apex; petiole 30-150 mm long, (0.8-)1.7-4.5 times as long as the lamina,sometimes
slightlywingedtowardsthe lamina,almostalwayswith a discolouredsectionat thejunctionwith the lamina.
Stipulesaxillary,convolute,40-60(-80) mm long, unrolledup to 15 mm wide, translucent,with hyaline
margins,persistent.Peduncles45-80(-200) mm long, 2-5 timesas long as the fruitingspike,as thickas the
stem, insertedin the axils of floatingand submergedleaves, rarelysuboppositeto submergedleaves. Spikes
cylindrical,15-40 mm long in fruit,contiguous.Flowersnumerous,with 4 carpels.Fruits(3.5-)3.7-4.5 mm
long, rugosewhen dried,dorsalkeel indistinct.
Stem anatomy
Steleof prototype,lobed,endodermisof 0-type, interlacunar
bundlespresentin 1 circleorabsent,subepidermal
bundlespresentin 1 incompletering,pseudohypodermis
present,2-3(-4) layered.
Distribution
SouthAmericasouthof 380 S (Argentine,Chile,FalklandIslands).
Note
(1) The morphologicalvariationand distributionof P linguatusis insufficientlyknown. Nevertheless,we
assumethatit formsa naturalgroupwith P fiyeri andP. amplifolius.
10. Potamogeton amplifolius TUCKERMAN,
Amer. J. Sci. Arts, ser. 2, 6: 225. 1848.
Spirillusamplifolius(TUCK.)NIEUWL.,
Amer.Midl.Naturalist3: 16. 1913.
= P subobtususHAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 147. 1916, pro hybr.P alpinusx
P nodosus.
262
G. Wiegleb & Z. Kaplan
= P amplifoliusf. homophyllusHAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5): 163. 1916.
= ? P.scoliophyllusHAGSTR., Kungl.SvenskaVetenskapsakad.
Handl.55(5): 164. 1916,prohybr.P amplifolius
x P. illinoensis.
Description
Rhizomeslenderto robust,terete,perennial.Stemunbranched
or sparinglybranched,slenderto robust,terete,
annualto perennial,overwinteringas shortenedshoots;specializeddormantturionsnotdeveloping.Submerged
leaves petiolateto subsessile;laminalanceolateto ovate or broadlyelliptical,folded and stronglyarcuate,
80-170(-210) mm long, 25-75 mm wide, (1.3-)2.0-3.8(-5.4) times as long as wide, bright green or
yellow-greento darkgreen,sometimeswitha brownishtinge,(21-)25-37(-4 1)-veined,withoutrowsof lacunae
borderingthe midrib,entireat margins,narrowlyto broadlycuneateat base, obtuseto acuteat apex;petiole
(2-)6-60 mm long, 0.02-0.30 times as long as the lamina.Intermediateleaves sometimespresent.Floating
leavespetiolate;laminabroadlyoblongor ellipticalto ovate,45-105 mmlong,22-50 mm wide, 1.8-2.9 times
as long as wide, opaque, coriaceous, bright green to olive green, sometimes with a reddish tinge,
(21-)29-41(-51)-veined, cuneateto roundedor subcordateat base, acuteto roundedor mucronateat apex;
petiole(45-)80-200 mm long, (0.7-)1.1-2.3 times as long as the lamina,rarelywith a discolouredsectionat
thejunctionwiththe lamina.Stipulesaxillary,convolute,35-1 l0(-185) mm long,translucent,decayingearly
to persistent.Peduncles50-85(-1 10) mm long, 1.0-2.5(-4.0) times as long as the fruitingspike,as thickas
or thickerthanthestem.Spikescylindrical,25-50 mmlong in fruit,contiguous.Flowersnumerous,with(2-)4
carpels.Fruits3.9-5.2(-5.7) mm long, dorsalkeel indistinct.
Stem anatomy
Stele of prototype, lobed, endodermisof 0-type, interlacunar
bundlespresent,multicellular,subepidermal
bundlesabsent,pseudohypodermis
present,1(-2)-layered.
Distribution
W, C andE NorthAmerica.
11. Potamogeton ferrugineus HAGSTROM,
Kungl. Svenska Vetenskapsakad. Handl. 55(5): 161.
1916.
P. apicalis HAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 156. 1916.
= ? P. spoliatusHAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5): 168. 1916.
-
Description
Rhizomeslenderto robust,terete,perennial,winterbudsnot seen. Stemunbranched,slenderto robust,terete,
annual,dark-spottednearthe base; specializeddormantturionsnot developing.Submergedleaves petiolate;
laminabroadlylanceolate,decayingearly,(80-)150-240 mm long, (18-)25-40 mm wide, 1.8-6.5 times as
long as wide,green,with a reddishor brownishtinge,especiallywhendried,13-23-veined,withnarrowrows
of lacunaeborderingthe midrib,entireat margins,cuneateat base, acute at apex;petiole (10-)40-140 mm
long, 0.05-0.45 times as long as the lamina.Floatingleaves petiolate;laminabroadlylanceolateto ovate or
elliptical,50-85(-120 mm) long, 15-38 mm wide, 1.8-3.5 times as long as wide, green, with a reddishor
brownishtinge, stronglyreddishbrownwhen dried, 15-23-veined,cuneateat base, obtuseto acuteat apex;
petiole40-80(-140) mm long, 0.8-1.5 times as long as the lamina.Stipulesaxillary,convolute,35-65 mm
long,translucent,
persistent,2-keeled at base.Peduncles40-90 mmlong, 1.5-4.1 timesas long as thefruiting
spike,as thickas or slightlythickerthanthe stem.Spikescylindrical,17-40(-60) mmlong in fruit,contiguous.
Flowersnumerous,with 4 carpels.Fruits3.5-4.5(-5.0) mm long, dorsalkeel distinct.
Stem anatomy
Stele of protoor trio(2) type,endodermisof 0-type, rarelyfaintU-type,interlacunar
bundlesabsentor 1 circle
present,scatteredsubepidermalbundlespresentor absent,pseudohypodermis
present,(l-)2(-3) layered.
Distribution
SouthAmerica(Argentina,Uruguay,Brazil).
Note
(1) The descriptionof P.ferrugineushasuntilrecentlybeenobscuredby confusionwithP illinoensis.Despite
ourinvestigationssomeuncertaintieswithrespectto distribution
andtaxonomicrelationof the speciesremain.
In particular,
plantsdescribedas P. spoliatusshow some deviatingcharacters.
Taxonomy of Potamogeton
263
12. Potamogeton stenostachys K. SCHUMANN
in MARTIUS,
Fl. Bras. 3(3): 687, t. 119, fig. 1. 1894.
Description
Rhizomeslenderto robust,terete,perennial,winterbudsnot seen. Stem unbranched,slender,terete,annual;
specializeddormantturionsnot developing.Submergedleaves petiolate;laminalanceolate,decayingearly,
60-105 mmlong, 12-20 mmwide, 3.0-7.5 timesas longas wide,brightgreento darkgreen,5-9(-l 1)-veined,
with narrowrows of lacunaeborderingthe midrib,entireat margins,cuneateat base, acuteat apex;petiole
65-90 mmlong,0.7-1.5 timesas longas thelamina.Floatingleavespetiolate;laminaellipticalto ovate,30-90
mmlong, 13-35 mmwide, 1.7-3.0 timesas long as wide,brightgreen,oftenwitha brownishor reddishtinge,
15-23-veined,cuneateto roundedat base, obtuseto subacuteat apex;petiole27-65(-120) mm long, 0.7-4.0
timesas longas thelamina.Stipulesaxillary,convolute,30-72 mmlong,opaque,persistent,whitish.Peduncles
25-140 mm long,0.8-3.0 timesas long as the fruitingspike,slightlythinnerthanthe stem.Spikescylindrical,
25-45 mm long in fruit,contiguous.Flowersnumerous,with 4 carpels.Fruits1.8-2.5, dorsalkeel indistinct.
Stem anatomy
Stele of trio type (2), endodermisof 0-type, interlacunar
bundlespresentin 2 circles, subepidermal
bundles
absent,pseudohypodermis
present,1-2-layered.
Distribution
SouthAmerica(Brazil).
Note
(1) P. stenostachysis insufficientlyknown,even thoughit is clearlydistinctfromotherSouthAmericantaxa.
The presentdescriptionis basedon the type specimenRiedel834 andthe herbarium
collectionsUle 1308 and
Ule 6942.
13. Potamogetonalpinus BALBIS,Mem. Acad. Sci. Turin, Sci. Phys. Math. 1, 10-11 (1802-1803):
329. 1804. ("alpinum")
P lucens var.P.alpinus (BALB.)FIORI,Fl. Anal. Ital. 1: 154. 1896. ("alpina")
= P. annulatus BELLARDI,Mem. Acad. Sci. Turin, Sci. Phys. Math. 1, 10-11 (1802-1803): 447, t. 1, fig. 2.
1804.
= P tenuifoliusRAF.,Med. Repos.,Hexade3, 2: 409. 1811. ("tenuifolium")
P alpinus subsp. tenuifolius (RAF.) HULTEN,Fl. Aleut. IsI. 65. 1937.
= P semipellucidusW.D.J.KOCHet Zlz, Cat.P1.Palatinat.5: 18. 1814. ("semipellucidum")
= P rufescens SCHRAD.ex CHAM.,Adnot. Fl. Berol. 5. 1815.
= P obscurusDC. in LAM.et DC., Fl. Fran. ed. 3, 6: 311. 1815.("obscurum")
= P purpurascens SEIDLex J. PRESLet C. PRESL,Fl. Cech. 37. 1819.
= P. microstachys WOLFG.in SCHULT.et SCHULT.
f., Mant. 3: 360. 1827.
= P obrutus A.W.WOOD,Class-book Bot. 176. 1845.
= P casparyi KOHTS,Oesterr. Bot. Z. 20: 289. 1870. ("Casparyi")
P alpinus proles casparyi (KOHTS)GRAEBN.in ENGL.,
Pflanzenr. 31 (IV.11): 74. 1907. ("Casparyi")
- P thomasiiA. BENN.,Ann. K. K. Naturhist.Hofmus.Wien7: 288. 1892,pro syn. ("Thomasii")
P stylatus HAGSTR.,
Bot. Not. 1908: 98. 1908.
-
-
P montanensisGAND.,Bull. Soc. Bot. France66: 304. 1919. ("montanense")
P palmeriiDRUCE,
List Brit.P1.ed 2. 116. 1928,nom. nud.("Palmeri")
Description
Rhizome slender, terete, perennial,with scaly apical turions.Stem unbranched,slender,terete, annual;
specializeddormantturionsnotdeveloping.Submergedleavespresent,absentin landforms,sessile,lanceolate
to oblong, (51-)70-180(-380) mm long, (7-)10-25(-33) mm wide, 4-10(-14) times as long as wide,
yellow-greento brightgreen,often with a reddishtinge,especiallystrongwhendried,(7-)9-15-veined, with
broadrowsof lacunaeborderingthe midrib,entireat margins,cuneateat base, obtuseto narrowlyobtuseand
slightlyhoodedat apex. Intermediateleaves sometimespresent.Floatingleaves presentor absent,petiolate;
laminaoblongor oblanceolateto obovate,(24-)42-90 mimlong, 8-25 mm wide, 2-6 timesas long as wide,
opaque,subcoriaceousto coriaceous,yellow-grcen,usuallywitha reddishor brownishtinge,especiallywhen
dried,9-19-veined,cuneateto attenuateat base,obtuseat apex;petiole 10-35 mm long,0.1-0.8 timesas long
as the lamina.Stipulesaxillary,convolute,(12-)18-35(-50) mm long, translucent,decayingearly.Peduncles
264
G. Wiegleb & Z. Kaplan
30-150(-310) mm long, 2-5(-9) times as long as the fruitingspike,as thickas the stem. Spikescylindrical,
15-40 mm long in fruit,contiguous.Flowersnumerous,with 4 carpels.Fruits2.6-3.7 mm long, dorsalkeel
distinct.
Stem anatomy
Stele of trio (2) type, endodermisof 0-type, interlacunarbundles absent, subepidermalbundles absent,
pseudohypodermis
absent,rarely1-layered.
Distribution
Circumboreal,
throughoutthe NorthernHemisphere.
Hybrids
13 x 1. P.xspathulatusSCHRAD.exW.D.J. KOCH
etZiz, Cat. Pi. Palatinat. 5:18.1814, pro sp. ("spathulatum")
[= P. alpinusx P. polygonifolius]
13 x 24. P. xnervigerWOLFG.in SCHULT.
et SCHULT.
f., Mant.3: 359. 1827, pro sp.
[= P alpinusx P. lucens]
P rufescensvar.b) nerviger(WOLFG.)
K. RICHT.,PI.Eur.1: 12. 1890.
P alpinusvar.purpurascenssubvar.nerviger(WOLFG.)ASCH.et GRAEBN.,Synops.Mitteleur.Fl. 1: 311.
1897.
_ P alpinusvar.nerviger(WOLFG.)
G. FIsCH.,Mitt.Bayer.Bot. Ges. 4(10): 153. 1930.
- P nervigerusWOLFG.,
Herb.Eichw.Skizze 125. 1830. [nonvidimus]
13 x 25. P. xnericius HAGSTR.,
Kungi. Svenska Vetenskapsakad. Handl. 55(5): 145. 1916.
[= P alpinusx P gramineus]
13 x 26. P. xprussicus HAGSTR.,Bot. Not. 1908: 103.1908.
[= P alpinusx P perfoliatus]
P johannis HESL.-HARR.,Occas. Notes Dept. Bot., King's Coll., Newcastle upon Tyne 2: 3. 1941.
13 x 28. P. xgriffithiiA. BENN.,J. Bot. 21: 65, t. 235. 1883. ("Griffithii")
[= P alpinus x P praelongus]
- P macvicarii A. BENN., Ann. Scott. Nat. Hist. 62: 106. 1907. ("Macvicarii")
13 x 35. P. xolivaceus BAAGOEex G. FISCH.,Ber. Bayer. Bot. Ges. 11: 33. 1907.
[= P alpinus x P crispus]
- P xvenustus BAAGOE,Actes 1. Congr. Intern. Bot. Paris 516. 1900, nom. nud.
= P xvenustus BAAGOEex A. BENN.,J. Bot. 45: 375. 1907.
- ? P. baagoei A. BENN. [apud GRAEBN.]in ENGL.,Pflanzenr. 31 (IV.11): 132. 1907, nom. nud. ("Baagoei")
= P xvenustus BAAGOEex HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 144. 1916, nom. illeg.
-
Note
(1) P alpinus might be sometimes confused with other similar plants. However, it is a taxonomically well
defined species. It shows an extreme regional and ecological polymorphism.
14. Potamogeton thunbergii CHAMISSO
et SCHLECHTENDAL,
Linnaea 2(2): 221, t. 6, f. 21. 1827.
("Thunbergii")
P americanus var. thunbergii (CHAM. et SCHLTDL.)A. BENN. in DYER, Fl. Capens. 7: 46. 1897.
("Thunbergii")
P fluitans proles thunbergii (CHAM.et SCHLTDL.)
GRAEBN.in ENGL.,Pflanzenr. 31 (IV.11): 61. 1907.
= P natans var. angustatus b) capensis CHAM.ex KUNTH,Enum. P1. 3: 128. 1841.
= P richardii SOLMSin SCHWEINF.,
Beitr. FH.Aethiop. 194. 1867. ("Richardi")
P americanus var. richardii (SOLMS)SOLMSex SCHWEINF.,Bull. Herb. Boissier 2, App. 2: 8. 1894.
("Richardi")
= P natans var. capensis T. DURANDet SCHINZ,Consp. Fl. Afric. 5: 494. 1894.
= P fibrosus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 160. 1916.
Description
Rhizome slender to robust, terete, perennial, with apical scaly turions. Stem unbranched, slender, terete, annual;
specialized dormant turions not developing. Submerged leaves petiolate; lamina lanceolate to oblong, decaying
early, sometimes the lower ones reduced to phyllodes, 80-200 mm long, 5-27 mm wide, 5-13 times as long
Taxonomy of Potamogeton
265
as wide, brightgreento darkgreen,9-17-veined, withnarrowrows of lacunaeborderingthe midrib,entireat
margins,narrowlycuneateat base, acuteat apex;petiole(10-)45-180 mm long, 0.2-1.8 times as long as the
lamina. Intermediateleaves often present. Floating leaves petiolate;lamina elliptical to oblong-ovate,
30-80(-124) mm long, (11-)20-40(-48) mm wide, 1.6-3.5(-5.0) timesas long as wide, opaque,coriaceous,
olive greento darkgreen, 11-25-veined,broadlycuneateto roundedat base, broadlyacute at apex;petiole
18-110(-195) mm long, (0.3-)0.6-3.0 times as long as the lamina,almostalwayswith a discolouredsection
at the junctionwith the lamina.Stipulesaxillary,convolute,25-40(-60) mm long, translucent,persistentto
decayingearly.Peduncles50-100 mm long, 2.0-3.5 times as long as the fruitingspike,as thickas the stem,
insertedintheaxilsof floatingleaves.Spikescylindrical,30-50 mmlongin fruit,contiguous.Flowersnumerous,
with 4 carpels.Fruits3.2-4.8 mm long, dorsalkeel distinct.
Stem anatomy
Stele of trio(2) type, endodermisof U-type,interlacunar
bundlespresentin 2-3 circles,subepidemalbundles
present,pseudohypodermis
present,1-layered.
Distribution
Africa(in particularSouthandEast Africa),Madagascar,
MascareneIslands?
Notes
(1) P thunbergiiis superficiallymorphologically
similarto P nodosus.However,accordingto its stemanatomy
and some morphologicalcharacterslike the presenceof phyllodialleaves andthe discolouredjoint at the top
of the petiole,it is moreclosely relatedto P natans.
(2) Theexactidentityof P xbunyonyiensis
DENNY
et LYE,Kew Bull.28(1): 120. 1973,introducedas a hybrid
P schweinfurthii
x P thunbergii,is stillunderconsideration
andcannotbe listedwithcertaintyamongconfirmed
hybrids.
15. Potamogeton parmatus HAGSTROM,
Bot. Not. 1908: 97. 1908.
Description
Rhizomeslender,terete,perennial,winterbudsnot seen. Stemunbranched,
slender,terete,annual;specialized
dormantturionsnotdeveloping.Submergedleavespetiolate;laminalanceolateto oblong,decayingearly,40-75
mm long, 6-16(-23) mm wide, 2.3-3.8 timesas long as wide, green,(5-)7-13-veined, with narrowrowsof
lacunaeborderingthe midrib,entireat margins,narrowlycuneateat base, acuteat apex;petiole70-195 mm
long, 1.6-3.3 timesas long as the lamina.Floatingleavespetiolate;laminaoblongor oblanceolateto obovate,
45-63 mmlong,7-26 mm wide, 2.1-4.2 timesas long as wide,opaque,coriaceous,olive greento darkgreen,
sometimes with a brownish tinge, (9-)11-19-veined, broadly cuneate at base, acute at apex; petiole
75-170(-280) mm long, 1.8-6.0 times as long as the lamina.Stipulesaxillary,convolute,30-45 mm long,
translucent,decayingearly.Peduncles50-120 mm long, 2-6 timesas long as the floweringspike,as thickas
the stem, insertedin the axils of floatingleaves. Spikes cylindrical,14-20 mm long in flower,contiguous.
Flowersnumerous,with 4 carpels.Fruitsnot seen.
Stem anatomy
Stele of protoor trio (2) type, endodermisof U-type,interlacunar
bundlespresentin 1 circle, subepidermal
bundlesabsentor a few present,pseudohypodermis
absentor 1-layered.
Distribution
Madagascar,
E Africa?
Note
(1) P parmatushasbeenrecordedonly froma restrictedgeographicalarea.It hasneverbeenre-collectedsince
its firstformaldescription(HAGSTROM
1908).Becauseof theuniquecharactercombination,however,we are
inclinedto maintainit as a separatespecies,beingclosely relatedto bothP thunbergiiandP schweinfurthii.
It may proveto be a hybridor an extrememorphotypeof one of these species(cf. P xbunyonyiensis,
DENNY
& LYE 1983).
16. Potamogeton natans Linnaeus, Sp. PI. 126. 1753.
-P
Spirillus natans (L.) NIEUWL.,Amer. Midl. Naturalist 3: 16. 1913.
natans [subsp.] a. vulgaris SCHUBL.et G. MARTENS,Fl. Wurttemb. 109. 1834, nom. inval.
266
G. Wiegleb & Z. Kaplan
- P natans [subsp.] a) vulgaris CELAK.,Analyt. Kvet. Cech, Mor. a Rak. Slezska ed. 3. 45. 1897, nom.
inval.
- P. serotinus SCHRAD.ex SCHULT.et SCHULT.
f., Mant. 3: 351. 1827, pro syn. ("serotinum")
= P. natans var. P. ovalifolius FIEBER in BERCHT.et FIEBER,Potam. Bohmens 23. 1838; FIEBERin BERCHT
et OPIZ,Oekon.-Techn. Fl. Bohm. 2(1): 260. 1838.
-P paludosus BOENN.ex STEUD.,Nomencl. Bot. ed. 2. 2: 384. 1841, pro syn.
= P natans var. P. prolixus W.D.J. KOCH,Syn. Fl. Germ. Helv. ed. 2. 775. 1844.
= P natans var. b. angustifolius G. MEY.,Fl. Hanov. Exscurs. 537. 1849, nom. illeg.
= P morongii A. BENN.,J. Bot. 39: 145. 1902. ("Morongii")
= ? P floridanus SMALL,Fl. Southeast. Unit. St. 37. 1903.
= P gessnacensis var. richtsfeldii f. hibernicus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 192.
1916.
P hibernicus (HAGSTR.)DRUCE,List Brit. P1. ed 2. 116. 1928.
Description
Rhizome slender to robust, rarely filiform, terete, perennial, overwintering with phyllodial shoots. Stem
unbranched or sparingly to richly branched, slender to robust, terete, annual to perennial, wintergreen,
dark-spottednear the base; winterbudsas axillary, short, leafy shoots, specialized dormantturionsnot developing.
Submerged leaves sessile; lamina reduced to linear phyllodes, 100-450(-610) mm long, 0.8-3.5 mm wide,
70-200(-300) times as long as wide, dark green, 1-3-veined, lateral veins inconspicuous, entire at margins,
straight at base, narrowly obtuse to acuminate at apex. Intermediateleaves rarely present, narrowly lanceolate,
long petiolate. Floating leaves petiolate; lamina oblong to broadly elliptical or broadly ovate, 40-100(-140)
mm long, (7-)20-45(-80) mm wide, 1.5-3.5(-5.2) times as long as wide, opaque, coriaceous, brown-green
or yellow-green to olive green or dark green, sometimes with a brownish tinge, 17-31(-35)-veined, cuneate
to rounded or subcordate at base, acute to obtuse at apex; petiole 50-150(-300) mm long, 0.7-5.0 times as
long as the lamina, almost always with a discoloured section at the junction with the lamina. Stipules axillary,
convolute, 40-170 mm long, translucent, persistent. Peduncles 35-90(-125) mm long, 1.2-3.0 times as long
as the fruiting spike, as thick as the stem. Spikes cylindrical, 20-60 mm long in fruit, contiguous. Flowers
numerous, with 4 carpels. Fruits 3.8-5.0 mm long, dorsal keel indistinct to distinct.
Stem anatomy
Stele of eight bundles or complex oblong type, endodermis of U-type, interlacunar bundles present in 3-4
circles, multicellular, subepidermal bundles present, pseudohypodermis present, 1-2-layered.
Distribution
Circumpolar, boreal and temperate regions of the Northern Hemisphere.
Hybrids
16 x 1. P xgessnacensis G. FISCH.,Mitt. Bayer. Bot. Ges. 1(37): 472. 1905. ("GeBsnacensis")
[= P natans x P polygonifolius]
16 x 20. P xschreberi G. FISCH.,Mitt. Bayer. Bot. Ges. 1(37): 471. 1905. ("Schreberi")
[= P natans x P. nodosus]
24 x 16. P xfluitans ROTH,Tent. Fl. Germ. 1: 72. 1788, pro sp.
[= P lucens x P natans]
-P natans [var.] P.fluitans (ROTH)CHAM.,Adnot. Fl. Berol. 4. 1815.
-P natans [subsp.] y. fluitans (ROTH)SCHUBL.et G. MARTENS,Fl. Wurttemb. 109. 1834.
= P oblongus [var.] ("spielart")a. fluitans (ROTH)G. MEY.,Chlon's Han. 520. 1836.
- P rothii A. BENN.ex G. FISCH.,Mitt. Bayer. Bot. Ges. 1(31): 362. 1904, nom. inval. ("Rothii")
- P
xcrassifolius FRYER,J. Bot. 28: 321, t. 299. 1890.
- P xolivaceus BAAGOE,Actes 1. Congr. Intern. Bot. Paris 516. 1900, nom. nud.
P xnoltei G. FISCH.,Mitt. Bayer. Bot. Ges. 37: 472. 1905, nom. illeg. ("Noltei"), non A. BENN. 1890.
- P noltei ser. harzii G. FISCH.,Ber. Bayer. Bot. Ges. 11: 57 et 145. 1907, nom. inval. ("Harzii")
- P noltei var. P. harzii G. FISCH.ex GRAEBN.in ENGL.,Pflanzenr. 31 (IV. 1I):137. 1907, nom. inval.
("Harzii")
= P harzii G. FISCH.,Mitt. Bayer. Bot. Ges. 3(5): 104. 1914. ("Harzii")
= P fluitans proles raunkiaeri G. FISCH.,Mitt. Bayer. Bot. Ges. 3(5): 103. 1914. ("Raunkiaeri")
- P fluitans ser. raunkiaeri (G. FISCH.)G. FISCH.,Mitt. Bayer. Bot. Ges. 4(10): 154. 1930, nom. inval.
Taxonomy of Potamogeton
267
= P. xsterilis HAGSTR., Kungl. Svenska Vetenskapsakad. Handl. 55(5): 238. 1916.
= P xsubrufus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 241. 1916.
25 x 16. P. xsparganiifolius LAEST.ex FR., Novit. Fl. Suec. Mant. 1: 9. 1832. ("sparganifolius")
[= P. gramineus x P natans]
-P natans proles sparganiifolius (LAEST.ex FR.) AsCH. et GRAEBN.,Synops. Mitteleur. Fl. 1: 304. 1897.
-P. natans subsp. sparganiifolius (LAEST.ex FR.) SCHINZet THELL.,Fl. Schweiz ed. 3. 2: 15. 1914.
= P. natans subsp. kirkii SYMEex HOOK.f., Stud. Fl. Brit. IsI. 371. 1870. ("Kirkii")
- P kirkii SYME,ENGL.Bot. ed. 3. 9: 31. 1869, pro syn. ("Kirkii")
P kirkii (SYMEex HOOKf.) SYMEex HOOKf., Stud. Fl. Br. Isl. ed. 3. 435. 1884.
P xtiselii K. RICHT.,P1. Eur. 1: 13. 1890. ("Tiselii")
= P dubius TISELIUS,Potamog. Suec. Exs., fasc. 1: [sched.] no. 19, notulae p. 5. 1894.
25 x 48. P xvariifolius THORE,Essai Chloris 47. 1803, pro sp. ("variifolius")
[= P. natans x P pusillus]
P gramineus subsp. variifolius (THORE)NYMAN,Consp. Fl. Eur. 4: 682. 1882.
-P javanicus subsp. variifolius (THORE)P. FOURNIER,
Quatre Fl. Fr. 140. 1935.
25 x 56. P. xyamagataensis KADONO
et WIEGLEB,
J. Jap. Bot. 62(3): 73. 1987.
[= P natans x P octandrus]
- P pleiophyllus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 159. 1916, p. p.
? 25 x 68. P. xnomotoensis KADONO
et T. NOGUCHI,
Acta Phytotax. Geobot. 42(2): 175. 1991, pro sp.
[= ? P natans x P pectinatus]
Notes
(1) P floridanus is a unique plant collected from a restricted area. Morphologically it is similar to a juvenile
P. natans. It differs from the type in its completely different shoot anatomy. Anatomical characters point to
hybridization with P illinoensis or P gramineus. Both its identity with P natans or a hybrid of this species
have been rejected in the past for phytogeographical reasons.
(2) The authenticcollection of P pleiophyllus includes both P xyamagataensis and P nodosus. Furtherspecimens
are listed in its protologue including also P distinctus and maybe even P natans. A lectotype specimen has to
be selected in the future to elucidate the identity with P. xyamagataensis.
(3) P xnomotoensis displays a unique charactercombination of a broad-leaved species with long adnate stipules.
It could represent a hybrid, a hybridogenous species or an extreme deviation of a broad-leaved species like
P. natans (for an analogous case of the last possibility see HELLQUIST
1978). Further research is necessary.
(4) The name "P fluitans" has been misapplied to almost all broad-leaved species with floating leaves. Most
of specimens named as such relate to P nodosus, but by no means all records of "P fluitans" can be explained
in this way. Despite the lack of type specimens we adopt the name for the hybrid P. natans x P lucens, being
aware of the fact that this hybrid still grows not far from the type locality in the same river.
17. Potamogeton
oakesianus
J.W. ROBBINSin GRAY,Manual Bot. North. U. S. ed. 5. 485. 1867.
("Oakesianus")
Description
Rhizome slender, terete, perennial. Stem unbranchedor sparingly branched, slender, terete, annual to perennial,
overwintering as shortened shoots; specialized dormant turions not developing. Submerged leaves sessile;
lamina reduced to linear phyllodes, 50-160 mm long, (0.2-)0.3-1.0 mm wide, 120-300 times as long as wide,
dark green, 1-3-veined, lateral veins inconspicuous, entire at margins, straight at base, narrowly obtuse to
acuminate at apex. Floating leaves petiolate; lamina oblong to elliptical or broadly ovate, (13-)22-40(-55)
mm long, (5-)10-22(-29) mm wide, 1.5-2.7 times as long as wide, opaque, coriaceous, bright green to olive
green, sometimes with a brownish tinge, (7-)9-19(-23)-veined, cuneate to rounded at base, broadly acute to
obtuse at apex; petiole 25-70(-100) mm long, 1.0-2.5 times as long as the lamina, often with a discoloured
section at the junction with the lamina. Stipules axillary, convolute, 10-40(-55) mm long, translucent,persistent.
Peduncles 25-60 mm long, 1.5-2.5 times as long as the fruiting spike, usually thicker than the stem. Spikes
cylindrical, 15-30 mm long in fruit, contiguous. Flowers numerous, with 4 carpels. Fruits 2.5-3.5(-3.7) mm
long, dorsal keel distinct.
268
G. Wiegleb & Z. Kaplan
Stem anatomy
Stele of trio type, endodermisof U-type, interlacunar
bundlesin 1-2 circles present,subepidermalbundles
present,pseudohypodermis
absentor present,1-layered.
Distribution
C andE NorthAmerica.
Note
(1) P. oakesianusis closely relatedto P natans.It comprisesmorphotypeswith a special characterpattern
distributedwithina limitedgeographicalarea.
18. Potamogeton papuanicus WIEGLEB,
Blumea 37: 379. 1993.
Description
Rhizomeslender,terete,perennial.Stem unbranchedor very sparinglybranched,slender,terete,annualor
perennial,continuinggrowthafterflowering;specializeddormantturionsnot developing.Submergedleaves
petiolateor sometimessubsessile;laminanarrowlyoblong to oblong-lanceolate,105-160 mm long, 12-30
mm wide,4-9 times as long as wide, brightgreen,sometimeswitha reddishtinge,7-13-veined, withnarrow
rows of lacunaeborderingthe midrib,entireat margins,cuneateto slightlycordateor sagittateat base,acute
at apex; petiole 5-45 mm long, 0.1-0.5 times as long as the lamina. Floating leaves petiolate;lamina
oblong-lanceolateto elliptical,65-115 mm long, 18-30 mm wide, 2-5 times as long as wide, translucent,
membranous
to subcoriaceous,brightgreen,sometimeswitha reddishorbrownishtinge,9-15-veined,cuneate
atbase,acuteatapex;petiole115-185 mmlong,0.5-3.0 timesas longas thelamina.Stipulesaxillary,convolute,
20-60 mmlong,translucent,
persistent.Peduncles130-180 mmlong, 5-7 timesas long as thefloweringspike,
thickerthanthe stem, insertedin the axils of floatingand submergedleaves. Spikes cylindrical,21-28 mm
long in flower,contiguous.Flowersnumerous,with 4 carpels.Fruitsnot seen.
Stem anatomy
Steleof protoor trio(2) type,endodermisof 0-type, interlacunar
bundlesabsent,subepidermal
bundlesabsent,
pseudohypodermis
absent.
Distribution
Papua-NewGuinea,LesserSundaIsles?
Note
(1) Bothmorphologyanddistributionof P papuanicusarestill insufficientlyknown.The speciesis relatedto
P distinctusandP. nodosus.
19. Potamogeton distinctus A. BENNETT,
J. Bot. 42: 72. 1904.
P digynusWALLICH,
Numer.List 181, no. 5177. 1832, nom.nud.
= P natansf. indicusMIQ.,Fl. Ind. Batav.,Suppl. 1 [= Fl. Ned. Ind., EersteBijv.], 2: 259, 3: 597. 1861.
("indica")
= P malaianusvar.tenuiorMIQ.,Ill. Fl. ArchipelInd. 1: 47. 1870.
= P.franchetiiA. BENN.et BAAGOE
ex A. BENN.,J. Bot. 45: 234. 1907. ("Franchetii")
= P tepperivar.a. attenuatusA. CAMUS
in LECOMTE,
Not. Syst. 1: 85. 1909.
= P tepperivar.P. subcordatusA. CAMUS
in LECOMTE,
Not. Syst. 1: 85. 1909.
= P longipetiolatusA. CAMUS
in LECOMTE,
Not. Syst. 1: 88. 1909.
= P. perversusA. BENN.,Philipp.J. Sci. 9: 343. 1914.
= P. alatus KoIDZ.,Bot. Mag. (Tokyo)43: 397. 1929.
= P fontigenusY.H.Guo, X.Z. SUNet H.Q.WANG,Bull. Bot. Res. North.-East.Forest.Inst.5(2): 133. 1985;
Y.H.Guo, H.Q. WANGet X.Z. SUN,Acta Bot. Bor.-Occid.Sin. 5(4): 301. 1985.
-
Description
Rhizomeslender,terete,perennial,with apicalwinterbuds.Stemunbranched
or sparinglybranched,slender,
terete,annual;specializeddormantturionsnotdeveloping.Submergedleavesmostlypresent,petiolate;lamina
oblongto lanceolate,decayingearly,sometimesthatof the lowest leaves reducedto phyllodes,45-140 mm
long, (5-)10-23 mm wide, 4-7 times as long as wide, brightgreento darkgreen,9-17-veined, with narrow
rows of lacunaeborderingthe midrib,minutelydenticulateat margins,cuneateat base, acuteat apex;petiole
30-190(-230) mm long, 0.5-5.0 timesas long as the lamina.Intermediate
leaves sometimespresent.Floating
Taxonomy of Potamogeton
269
leaves petiolate; lamina oblong to broadly elliptical or obovate, (30-)50-95(-125) mm long, 10-35(-50) mm
wide, 2-6 times as long as wide, opaque, coriaceous, brightgreen, sometimes with a reddish tinge, 11-1 9-veined,
narrowly cuneate to broadly cuneate at base, acute to obtuse at apex; petiole (45-)80-260(-390) mm long,
0.5-7.0 times as long as the lamina. Stipules axillary, convolute, 40-105 mm long, translucent, persistent.
Peduncles 45-105 mm long, 1-3 times as long as the fruiting spike, slightly thicker than the stem, inserted in
the axils of floating leaves. Spikes cylindrical, 25-80 mm long in fruit, contiguous. Flowers numerous, with
1-2(-4) carpels. Fruits 2.9-3.7 mm long, dorsal keel more or less distinct.
Stem anatomy
Stele of trio (1,2) type, endodermis of 0-type, interlacunarbundles absent, subepidermal bundles mostly absent,
pseudohypodermis mostly absent, rarely 1-layered.
Distribution
E and SE Asia, Pacific islands.
Hybrids
19 x 21. P. xmalainoides MIKI,
WaterPhan. Japan 20. 1937.
[= P. distinctusx P. wrightii]
Notes
(1) P distinctus is closely related to P. nodosus. Because transitional plants are sometimes found it may be
regarded in the future as its geographical subspecies (see WIEGLEB1990a).
(2) The identity of P xmalainoides might be doubted since it cannot be excluded that its type specimen represents
a shallow water form of P. wrightii with floating leaves. However, intermediate forms between the parent
species occur without doubt, but their origin has not been satisfactorily explained.
20. Potamogeton nodosus POIRETin LAMARCK,
Encycl. Meth. Bot., Suppl. 4: 535. 1816.
("nodosum")
P.fluitans proles rothii G. FISCH.,Mitt. Bayer. Bot. Ges. 3(5): 103. 1914. ("Rothii")
- P indicus ROXB.,Hort. Bengal. 12. 1814, nom. nud.
- P indicus ROXB.in CAREY,Fl. Ind. 1: 471. 1820, nom. illeg. ("indicum"), non ROTHex ROEM.et SCHULT.
1818.
P roxburghianus SCHULT.
et SCHULT.f., Mant. 3: 367. 1827. ("Roxburghianus")
= P petiolaris C. PRESLin J. PRESLet C. PRESL,Delic. Prag. 151. 1822, nom. illeg. ("petiolare"), non
P petiolaris RAF. 1811.
-P natans subsp. y. petiolaris [C. PRESL]ARCANG.,Comp. Fl. Ital. 642. 1882.
-P fluitans proles petiolaris [C. PRESL]GRAEBN.in ENGL.,Pflanzenr. 31 (IV.'1): 59. 1907.
- P canariensis LINKin BUCH,Phys. Beschr. Canar. Ins. 138. 1825.
P petiolatus WOLFG.in SCHULT.et SCHULT.f., Mant. 3: 352. 1827.
- P leschenaultii CHAM.et SCHLTDL.,
Linnaea 2(2): 223, t. 6. fig. 23. 1827. ("Leschenaultii")
= P occidentalis SIEBERex CHAM.et SCHLTDL.,
Linnaea 2(2): 224. 1827.
= P americanus CHAM.et SCHLTDL.,Linnaea 2(2): 226. 1827.
= P natans var. angustatus f) americanus (CHAM.et SCHLTDL.)
KUNTH,Enum. P1. 3: 128. 1841.
= P fluitans subsp. americanus (CHAM.et SCHLTDL.)
MAGNIN,Bull. Soc. Bot. France 43: 436. 1896.
- P fluitans subsp. americanus (CHAM.et SCHLTDL.)
GRAEBN.in ENGL.,Pflanzenr. 31 (IV.l 1): 60. 1907.
[isonymum]
- P syriacus CHAM.et SCHLTDL.,
Linnaea 2(2): 227. 1827.
P fluitans proles syriacus (CHAM.et SCHLTDL.)
GRAEBN.in ENGL.,Pflanzenr. 31 (IV.l 1): 60. 1907.
= P marianensis CHAM.et SCHLTDL.,Linnaea 2(2): 228. 1827.
= P mascarensis CHAM.et SCHLTDL.,Linnaea 2(2): 228. 1827.
P fluitans proles mascarensis (CHAM.et SCHLTDL.)
GRAEBN.in ENGL.,Pflanzenr. 31 (IV.I 1): 60. 1907.
-P americanus subsp. mascarensis (CHAM.et SCHLTDL.)
A. BENN.,J. Bot. 46: 160. 1908.
= ? P owaihiensis CHAM.et SCHLTDL.,Linnaea 2(2): 228. 1827. ("O-Waihiensis")
-? P. fluitans proles owaihensis (CHAM.et SCI11rDL.)GRAEBN.in ENGL.,Pflanzenr. 31 (IV.11): 60. 1907.
= P malaianus MIQ.,Ill. Fl. Archipel Ind. 1: 46. 1870. ("malaina")
- P mexicanusA. BENN.,J. Bot. 25: 289. 1887.
- ? P peruvianus C. PRESLex A. BENN.,J. Bot. 28: 298. 1890, pro syn. ("peruviana")
270
G. Wiegleb & Z. Kaplan
= P delavayiA. BENN.,J. Bot. 30: 228. 1892. ("Delavayi")
= P lonchitesvar.novaeboracensisMORONG,Mem.TorreyBot. Club3(2): 20. 1893.
= P druceiFRYER,Potamoget.Brit. Isles 31, t. 21. 1898. ("Drucei")
= P. semicoloratusA. BENN.,J. Bot. 48: 150. 1910.
= P stagnorus HAGSTR.in R.E. FR., Wiss. Ergenb. Schwed. Rhod.-Kongo-Exped. 1911-1912, 1(2): 187. 1916.
("stagnorum")
= P. rotundatusHAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5): 153. 1916.
= ? P insulanusHAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5): 154. 1916.
Description
Rhizome slender, terete, perennial, with apical winter buds. Stem unbranched or sparingly branched, slender,
terete, annual; specialized dormant turions not developing. Submerged leaves present, absent in landforms,
petiolate; lamina narrowly oblong to oblanceolate-oblong, sometimes that of the lowest leaves reduced to
phyllodes, (47-)160-280(-350)
mm long, (1 -)22-38 mm wide, 5-9 times as long as wide, bright green to
dark green, (7-)11-21-veined, with narrow to broad rows of lacunae borderingthe midrib, minutely denticulate
at margins, narrowly cuneate at base, acute at apex; petiole (12-)60-180(-250) mm long, 0.2-1.5 times as
long as the lamina. Floating leaves present, rarely absent, petiolate; lamina oblong to broadly elliptical,
(35-)60-130 mm long, (I1-)25-50 mm wide, 2.0-4.5 times as long as wide, opaque, coriaceous, bright green
to olive green, sometimes with a reddish tinge, ( I1-) 15-23-veined, narrowly cuneate to rounded at base, obtuse
to broadly acute at apex; petiole 30-210 mm long, 0.5-2.3 times as long as the lamina. Stipules axillary,
convolute, (33-)45-125 mm long, translucent, persistent or decaying. Peduncles (32-)45-130 mm long, 2-3
times as long as the fruiting spike, thicker than the stem, inserted in the axils of floating leaves, rarely of
submerged leaves. Spikes cylindrical, 25-70 mm long in fruit, contiguous. Flowers numerous, with (2-)4(-5)
carpels. Fruits 2.7-4.1(-4.3) mm long, dorsal keel distinct.
Stem anatomy
Stele of trio (1,2) or proto type, endodermis mostly of 0-type, sometimes of O-U-type, interlacunarbundles
absent, rarely a few present, subepidermal bundles absent, rarely a few present, pseudohypodermis absent.
Distribution
Subcosmopolitan; Europe, Africa, temperate and tropical Asia, Australia, Pacific islands, North America, N
and C South America.
Hybrids
16 x 20. P. xschreberi G. FISCH.,
Mitt.Bayer. Bot. Ges. 1(37):471. 1905. ("Schreberi")
[= P natansx P nodosus]
? 22 x 20. P. xfaxonii MORONG,
Mem.TorreyBot. Club 3(2): 22, t. 32. 1893, pro sp. ("Faxonii")
[= ? P illinoensisx P nodosus]
P xchamplainiiA. BENN.,J. Bot. 46: 248. 1908. ("Champlainii")
- P xrugeliiA. BENN.,J. Bot. 46: 250. 1908, nom. nud. ("Rugelii")
Notes
(1) P nodosus is one of the most polymorphic Potamogeton species. It shows several regionally distinct
morphotypes as well as an extreme phenotypic plasticity all over its range.
(2) The southern limits of the distribution of P nodosus in South America and the Malesia-Australia area is
unclear.Confusionwith species like P linguatus,P ferrugineus,P. tepperi,andP sulcatusis common.
(3) The identity of P owaihiensis is questionable. The original material could not be studied. The name has
been placed into the synonymy of P nodosus by several authors. However, broad-leaved specimens from
Hawaii collected later are more similar to P solomonensis than to P nodosus.
(4) P xfaxonii is provisionally placed here as a hybrid, but its exact identity has not been proved so far. Because
of the phenotypic plasticity of the parent species P nodosus hybrids are generally difficult to verify without
experimental crossing.
21. Potamogeton wrightii MORONG,
Bull. Torrey Bot. Club 13: 158, t. 59. 1886. ("Wrightii")
= P mucronatus C. PRESL,Epimel. Bot. 245. 1851. ("1849"), nom. illeg., non SCHRAD.ex SONDER1850.
= ? P. sumatranus MIQ., Fl. Ind. Batav., Suppl. 1 [= Fl. Ned. Ind., Eerste Bijv.], 2: 259, 3: 597. 1861.
-
P japonicus
FRANCH.
et SAV.,Enum. Pi. Jap. 2: 15. 1877, nom. nud.
Taxonomy of Potamogeton
-
-
271
P tretocarpus MAXIM.ex A. BENN.,J. Bot. 29: 154. 1891, pro syn.
P tonkinensis A. CAMUSin LECOMTE,Not. Syst. 1: 86. 1909.
- P. distinctusvar.tonkinensis(A. CAMUS)
CUONG
in CUONG
et J.E. VIDAL,Fl. CambodgeLaos Vietnam
20: 58. 1983, nom. inval.
P hindostanicus HAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5): 156. 1916.
P miyakezimensis HONDA,Bot. Mag. (Tokyo)50: 435. 1936.
P jeholensis KITAGAWA,
J. Jap.Bot. 44(6): 182. 1969.
Description
Rhizomeslender,terete,perennial,with apicalwinterbuds.Stemunbranchedor sparinglybranched,slender,
terete,annual;specializeddormantturionsnot developing.Submergedleaves petiolate;laminalanceolateor
mostly oblong to narrowlyoblong, with parallelmargins,sometimesthat of the lowest leaves reducedto
phyllodes,80-200(-310) mm long, (7-)14-20(-27) mm wide,4-10(-17) timesas long as wide,brightgreen
to yellow-green,9-13-veined, with narrowrows of lacunaeborderingthe midrib,minutelydenticulateat
margins,narrowlycuneateat base, mucronateat apex;petiole(16-)30-70(-140) mm long, 0.1-1.0 times as
long as thelamina.Intermediate
leavessometimespresent.Floatingleavesusuallyabsentor sometimespresent,
petiolate;laminaoblongto elliptical,52-125 mmlong, 12-25 mmwide,2.5-8.0 timesas long as wide,opaque,
coriaceous,brightgreen,sometimeswith a reddishtinge, 11-25-veined,cuneateat base, mucronateat apex;
petiole 25-135 mm long, 0.5-2.0 times as long as the lamina.Stipulesaxillary,convolute,25-85 mm long,
translucent,
persistent.Peduncles46-70(-105) mmlong, 1-2 timesas longas thefruitingspike,slightlythicker
thanthestem.Spikescylindrical,25-56 mmlong in fruit,contiguous.Flowersnumerous,with4 carpels.Fruits
2.0-3.3 mm long, with a ventralprotrusion,dorsalkeel moreor less distinct.
Stem anatomy
Steleof trio,rarelyof prototype,endodermismostlyof U-type,sometimes0-type, interlacunar
bundlespresent,
in 1-2(-3) circles,subepidermal
bundlesabsent,rarelya few present,pseudohypodermis
present,1-layered.
Distribution
C, E andSE Asia, Pacific islands.
Hybrids
19 x 21. P. xmalainoides MIKI,Water Phan. Japan 20. 1937.
[= P distinctus x P. wrightii]
24 x 21. P. xinbaensis KADONO,
Acta Phytotax. Geobot. 34(1-3): 54. 1983.
[= P lucens x P wrightii]
26 x 21. P. xanguillanus KOIDZ.,
Bot. Mag. (Tokyo) 43: 398. 1929.
[= P perfoliatus x P wrightii]
? P. intortusifolius J.B. HE, L.Y. ZHOUet H.Q. WANG,Bull. Bot. Res. North-East.Forest.Inst. 8(3): 125.
1988.
37 x 21. P. xphilippinensis A. BENN.,PHILIPP.
J. SCi. 9: 342. 1914.
[= P maackianus x P wrightii]
Notes
(1) P. wrightiiis a clearlycircumscribedspecies.Nevertheless,confusionhas occurreduntilrecentlywith P
lucens, P. distinctus and P. nodosus.
(2) The species here called P wrightiiwas generallytreatedunderthe name "P malaianusMIQ."until the
typificationof thatnamewas carriedout (WIEGLEB1990b).The typespecimenof P malaianusactuallyrelates
to P. nodosus.
(3) P sumatranusMIQ.differsfromthe typein certaincharacters(abundant
formationof floatingleaves,wider
submergedleaves,lowernumberof interlacunar
bundles,see WIEGLEB1990bfor details).At presentit cannot
be decidedwhetherthis is a regionalmorphotypeof P wrightii,a hybrid,or a species in its own right.In the
firstmentionedcase nomenclatural
consequencesarise.
(4) P xanguillanushasalso beendescribedunderthe informalnamePotamogetonsp. B by LEACH
& OSBORNE
(1985).
(5) P xphilippinensishas been describedfrom a collectionwhich may also containordinaryP maackianus.
Lectotypification
will be carriedout in the future.
272
G. Wiegleb&Z. Kaplan
22. Potamogeton illinoensis MORONG,
Bot. Gaz. (Crawfordsville) 5: 50. 1880.
= P. lucens var. connecticutensisJ.W. ROBBINS
in A. GRAY,ManualBot. North.U. S. ed. 5. 488. 1867.
("Connecticutensis")
P.angustifoliusvar.connecticutensis
(J.W.ROBBINS)
A. BENN.,J. Bot. 39: 199. 1901.("Connecticutensis")
= P lucenssubsp.brasiliensisA. BENN.ex GRAEBN.
in ENGL.,Pflanzenr.31 (IV.11): 79. 1907.
-P brasiliensis(A. BENN.ex GRAEBN.)
A. BENN.,J. Bot. 48: 150. 1910.
= P zizii var.il. gracilis A. BENN.ex GRAEBN.
in ENGL.,
Pflanzenr.31 (IV.11): 83. 1907.
= P. zizii var.4. porrectifoliusA. BENN.ex GRAEBN.
in ENGL.,Pflanzenr.31 (IV.11): 83. 1907.
= P curvatusA. BENN.,J. Bot. 46: 249. 1908, pro hybr.P. angustifoliusx P. lucens.
= P illinoensisf. rosulatusHAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 199. 1916.
= P illinoensisf. homophyllusHAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 199. 1916.
= P fragillimusHAGSTR.,
Handl.55(5): 202. 1916.
Kungl.SvenskaVetenskapsakad.
= P macrophylloides
HAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 202. 1916.
= P pulchelliformisHAGSTR.,
Ark.Bot. 17(7): 12. 1922.
= P pederseniiTUR,Darwiniana24(1-4): 253. 1982.
= ? P dunicolaTUR,Darwiniana24(1-4): 254. 1982.
Description
Rhizomeslenderto robust,terete,perennial,withapicalwinterbuds.Stemunbranched
or sparinglybranched,
slenderto robust,terete,annual;specializeddormantturionsnotdeveloping.Submergedleavessessileto shortly
petiolate;laminanarrowlyoblongor oblanceolateto elliptical,sometimesthatof the lowest leavesreducedto
phyllodes,(50-)70-180(-220) mmlong,(4-)15-40(-53) mmwide,3.5-7.0 timesas longas wide,yellow-green
to brightgreen,sometimeswith a reddishor brownishtinge, (7-)9-17(-19)-veined, with or withoutnarrow
rows of lacunaeborderingthe midrib,minutelydenticulateto entireat margins,cuneateat base, mucronateat
apex;petiole0-21(-40) mm long, 0.0-0.2(-0.3) times as long as the lamina.Intermediate
leaves sometimes
present. Floating leaves present or absent, petiolate; lamina oblong to elliptical or ovate-elliptical,
(40-)52-125(-190) mm long, 19-65 mm wide, 1.9-3.1 times as long as wide, opaque,subcoriaceousto
coriaceous,yellow-greento darkgreen, sometimeswith a brownishtinge, (11-)13-29-veined, cuneateto
roundedor subcordateat base, obtuseor mucronateto acuteat apex;petiole (8-)14-90 mm long, 0.1-0.8
timesas longas thelamina.Stipulesaxillary,convolute,(13-)25-80 mmlong,translucent,
persistent.Peduncles
35-130(-310) mm long, 0.8-3.0(-5.0) timesas long as the fruitingspike,as thickas or slightlythickerthan
the stem.Spikescylindrical,20-65 mmlong in fruit,contiguous.Flowersnumerous,with(2-)4 carpels.Fruits
2.7-3.6(-3.9) mm long, dorsalkeel distinct.
Stem anatomy
Stele of protoor trioto oblongtype,endodermisof U-type,rarely0-type, interlacunar
bundlespresent,in 1-2
circles, the inner one complete, well developed, subepidermalbundles present, incomplete,or absent,
pseudohypodermis
present,1-layered,or absent.
Distribution
NorthAmericaandSouthAmerica.
Hybrids
? 22 x 20. P. xfaxonii MORONG,
Mem.TorreyBot. Club 3(2): 22, t. 32. 1893, pro sp. ("Faxonii")
[= ? P illinoensisx P nodosus]
25 x 22. P xdeminutus HAGSTR.,
Kungi.Svenska Vetenskapsakad.Handl.55(5): 209. 1916.
[= P gramineusx P. illinoensis]
? P. gramineusvar.spathulaeformis
J.W.ROBBINS
in A. GRAY,ManualBot. North.U. S. ed. 5. 487. 1867.
("spathulxformis")
- ? P spathaeformis
TUCK.ex J.W.ROBBINS
in A. GRAY,ManualBot. North.U. S. ed. 5. 487. 1867,pro
syn. ("spatheformis")
? P xspathulaeformis
(J.W.ROBBINS)
MORONG,
Mem.TorreyBot. Club3(2): 26, t. 35. 1893.
? P angustifoliusvar.methyensisA. BENN.,J. Bot. 29: 151. 1891.("Methyensis")
- ? P zizii var.methyensisA. BENN.in MACO'IN,
Cital. Canad.P1.5: 370. 1890,nom. nud.
In ENGL.,
_ ? P zizii var.methyensis(A. BENN.)GRAEBN.
Pflanzenr.31 (IV.l 1): 89. 1907.
? P xmethyensis(A. BENN.)A. BENN.,Trans.& Proc.Bot. Soc. Edinburgh29(1): 50. 1924.
- P xpseudolucens
HAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 199. 1916.
Taxonomy of Potamogeton
273
= P xpseudoziziiHAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 210. 1916. ("pseudo-Zizii")
Notes
(1) P. illinoensisis a polymorphicspecies which has been establishedby North Americanauthorsas an
independententitysince the beginningof this century.Nowadaysthe conceptincludesalso plantsfromSouth
America.The species is very closely relatedto P lucens.
(2) P dunicolais eitheran aberrantformof P illinoensisor a non-floatingleavedformof P linguatus.Stem
anatomyseems to justify the first assumption(see TUR1982).
23. Potamogeton schweinfurthii A. BENNETTin DYER, Fl. Trop. Afr. 8: 220. 1901.
("Schweinfurthii")
- P capensisSCHEELE
ex A. BENN.,Ann. K. K. Naturhist.Hofmus.Wien7: 287. 1892, nom. nud.
- P capensis SCHEELE
ex A. BENN.in DYER,Fl. Capens. 7: 46. 1897, pro syn.
- P lucens var. azoricus A. BENN.,J. Bot. 42: 71. 1904, nom. nud.("azorica")
- P azoricus A. BENN.ex HAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5): 198 et 265. 1916, nom.
nud.
= ? P chamissoi A. BENN.,J. Bot. 42: 74. 1904. ("Chamissoi")
= ? P repensHAGSTR.
in R.E. FR.,Wiss. Ergenb.Schwed.Rhod.-Kongo-Exped.
1911-1912, 1(2): 185. 1916.
= P nodosus var. billotii f. angustissimus HAGSTR.in R. E. FR., Wiss. Ergenb. Schwed. Rhod.-Kongo-Exped.
1911-1912, 1(2): 186. 1916.
= P promontoricusHAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 182. 1916.
= P capensisSCHEELE
ex HAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 203. 1916.
= P venosus A. BENN.,Trans.& Proc.Bot. Soc. Edinburgh29(1): 52. 1924.
Description
Rhizomeslender,terete,perennial,withapicalwinterbuds.Stemsparinglyto richlybranched,slender,terete,
annual;specializeddormantturionsnot developing.Submergedleaves sessile to shortlypetiolate;lamina
narrowly lanceolate to oblong-elliptical, sometimes that of the lowest leaves reduced to phyllodes,
52-170(-235) mm long, (3-)7-28 mm wide, 4-17(-21) timesas long as wide, yellow-greento brightgreen,
often with a reddishor brownishtinge, 7-11-veined, with or withoutnarrowrows of lacunaeborderingthe
midrib,minutelydenticulate,cuneateat base,mucronateatapex;petiole0-25(-65) mmlong,0.00-0.15(-0.35)
timesas long as the lamina.Intermediate
leaves sometimespresent,insteadof floatingleaves.Floatingleaves
presentor often absent,petiolate;laminaoblongto ellipticalor ovate,43-130 mm long, 12-30 mm wide, 2-6
timesas long as wide, opaque,subcoriaceousto coriaceous,yellow-greento darkgreen,with a reddishtinge,
11-21-veined,cuneateto roundedat base, obtuseto acuteat apex;petiole 14-63 mm long, 0.1-0.6 timesas
long as thelamina.Stipulesaxillary,convolute,20-62 mmlong, translucent,
persistent.Peduncles35-250 mm
long, 2-3 times as long as the fruitingspike, slightlythickerthanthe stem, mostly terminalor lateralin the
axils of submergedleaves, sometimesin the axils of floatingleaves. Spikes cylindrical,30-90 mm long in
fruit,contiguous.Flowersnumerous,with 4 carpels.Fruits3.0-3.9 mm long, dorsalkeel distinct.
Stem anatomy
Steleof protoortrioto oblongtype,endodermisof U-type,interlacunar
bundlespresent,in 1circle,subepidermal
bundlesabsentor scatteredones present,pseudohypodermis
present,1-layered.
Distribution
MascareneIslands,the Azores,Mediterranean
Africa,Madagascar,
islands?,SW Asia?
Hybrids
? 26 x 23. P. xvaginans (BOJER
ex A. BENN.)HAGSTR.,
Kungi. Svenska Vetenskapsakad.Handl.55(5):
280. 1916, pro sp.
[= ? P perfoliatus x P schweinfurthii]
_ P lucens subsp. vaginans BOJERex A. BENN.,Annuaire Conserv.Jard.Bot. Geneve9: 94. 1905.
Notes
(1) P schweinfurthii is closely related to P lucens and P illinoensis. It is more widespread than formerly
assumed.However,the exactgeographicaldelimitationfromP lucensis unknown,in particularin theAtlantic
Islands,the Mediterranean
andSW Asia. Transitional
formsof unknownstatusareknowne.g. fromPalestine,
Greece, and Iraq.
274
G. Wiegleb & Z. Kaplan
(2) P chamissoimost probablyrepresentsan apetiolateform of P schweinfurthii.Unfortunately,its type
specimenis badlypreserved.Specimenscollectedlaterunderthatnamereferto P nodosus.
(3) P xvaginansis provisionallyplaced here as this hybrid.Morphologyand distributionare insufficiently
known.As far as is known,it shows a morphologicalvariationpatternanalogousto P xsalicifolius.
24. Potamogeton lucens Linnaeus, Sp. PI. 126. 1753.
= Spirilluslucens(L.) NIEUWL.,Amer.Midl.Naturalist3: 17. 1913.
= P acuminatus SCHUMACH.,
Enum.P1. 1: 49. 1801. ("acuminatum")
= P lucens [var.]y acuminatus(SCHUMACH.)
RCHB.,Icon. Fl. Germ.Helv. 7: 23. 1845.
= P longifoliusJ. GAY in LAM.,Encycl. M6th. Bot., Suppl. 4: 535. 1816. ("longifolium")
- P lucens subsp. longifolius (J. GAY) MAGNIN,Bull. Soc. Bot. France 43: 440. 1896.
= P volhynicus BESSERex ROEM.et SCHULT.,Syst. Veg. ed. 16. 3: 509. 1818.
= P cornutus J. PRESLet C. PRESL,Fl. Cech. 37. 1819. ("comutum")
_ P caudatus SEIDLex OPIZ,Boheims Phaner. Crypt. Gewachse 23. 1823, nom. illeg. ("caudatum")
= P lucens var. P. macrophyllus WALLR.,Sched. Crit. 1: 65. 1822. ("macrophylla")
= P macrophyllus WOLFG.in SCHULT.et SCHULT.f., Mant. 3: 358. 1827.
= P lucens subsp. macrophyllus (WOLFG.)NYMAN,Consp. Fl. Eur. 4: 682. 1882.
= P gaudichaudii CHAM.et SCHLTDL.,Linnaea 2(2): 199. 1827. ("Gaudichaudii")
- P lucens var. teganumensis MAKINO,Bot. Mag. (Tokyo) 19: 142. 1905.
_ P teganumensis (MAKINO)MAKINO,Bot. Mag. (Tokyo) 26: 122. 1912.
= P dentatus HAGSTR.,Bot. Not. 1908: 101. 1908.
= P sinicus MIGO,J. Shanghai Sci. Inst., sect. 3, 3: 2. 1934.
= P lucens subsp. sinicus (MIGO)HARA,J. Jap. Bot. 60(8): 238. 1985.
Description
Rhizome slender to robust, terete, biennial to perennial, with apical winter buds. Stem sparingly to richly
branched, slender to robust, terete, annual; specialized dormant turions not developing. Submerged leaves
shortly petiolate; lamina narrowly oblong to broadly elliptical, sometimes that of the lowest leaves reduced to
phyllodes, (49-)70-200(-300)
mm long, (10-)25-65 mm wide, (2-)3-6(-10)
times as long as wide,
yellow-green to bright green, 9-11 -veined, without rows of lacunae borderingthe midrib, denticulate at margins,
broadly to narrowly cuneate at base, mucronate at apex; petiole 2-7(-15) mm long, 0.03-0.10 times as long
as the lamina. Floating leaves always absent. Stipules axillary, convolute, (20-)30-80(-1 10) mm long,
translucent, persistent. Peduncles 50-200(-350) mm long, 2-3(-5) times as long as the fruiting spike,
conspicuously thicker than the stem. Spikes cylindrical, 25-70 mm long in fruit, contiguous. Flowers numerous,
with 4(-6) carpels. Fruits 3.2-4.5 mm long, dorsal keel distinct.
Stem anatomy
Stele mostly of oblong type, sometimes of proto or trio type, endodermis of U-type, interlacunar bundles
present, multicellular, in 1-3 circles, subepidermal bundles present, often in incomplete circle,
pseudohypoderrmispresent, 1-layered.
Distribution
Europe, N and E? Africa, W, N and E Asia (southwards to Luzon).
Hybrids
13 x 24. P. xnervigerWOLFG. in SCHULT.
et SCHULT.
f., Mant. 3: 359. 1827, pro sp.
[= P alpinus x P lucens]
24 x 16. P. xfiuitans ROTH,Tent. Fl. Germ. 1: 72. 1788, pro sp.
[= P lucens x P natans]
24 x 21. P. xinbaensis KADONO,
Acta Phytotax. Geobot. 34(1-3): 54. 1983.
[= P lucens x P wrightii]
25 x 24. P. xangustifolius J. PRESLin BERCHT.
et J. PRESL,Rostlinaci 1, fasc. Zabnjkowite 19. 1821, pro sp.
[= P gramineus x P lucens]
- P zizii MERT.et W.D.J. KOCH,Rohlings Deutschl. Fl. ed. 3. 1: 845. 1823, pro syn. ("Zizii")
- P lucens [var.] &.coriaceus MERT.et W.D.J. KOCH,R6hlings Deutschl. Fl. ed. 3. 1: 850. 1823.
_ P lucens var. y. amphibius FR., Novit. Fl. Suec. ed. 2. 34. 1828, nom. illeg.
Taxonomy of Potamogeton
275
_ P coriaceus (MERT.et W.D.J. KOCH)FRYERex A. BENN.,J. Bot. 24: 223. 1886.
= P xzizii W.D.J. KOCHex ROTH,Enum. P1. Phaen. Germ. 1(1): 531. 1827, pro sp. ("Zizii")
P gramineus var. y. zizii (W.D.J. KOCHex ROTH)KUNTH,Enum. P1. 3: 131. 1841. ("Zizii")
P. heterophyllus var. c. zizii (W.D.J. KOCHex ROTH)BOREAU,Fl. Centre France ed. 3. 2: 600. 1857.
("Zizii")
P lucens var. P. zizii (W.D.J. KOCHex ROTH)ASCH.,Fl. Brandenb. 1: 660. 1864. ("Zizii")
P lucens subsp. zizii (W.D.J. KOCHex ROTH)NYMAN,Consp. Fl. Eur. 4: 682. 1882.
Spirillus zizii (W.D.J. KOCHex ROTH)NIEUWL.,Amer. Midl. Naturalist 3: 19. 1913. ("Zizii")
= P lucens var. b. heterophyllus FR., Novit. Fl. Suec. ed. 2. 34. 1828.
= P coriaceus FRYER,J. Bot. 27: 8. 1889, nom. illeg., non (MERT.et W. D. J. KOCH)FRYERex A. BENN.
1886.
= P. xbabingtonii A. BENN.,J. Bot. 32: 204. 1894. ("Babingtonii")
= P xheidenreichii ASCH.et GRAEBN.,Synops. Mitteleur. Fl. 1: 327. 1897. ("Heidenreichii")
= P xdecipiens var. berolinensis ASCH.et GRAEBN.,Synops. Mitteleur. Fl. 1: 331. 1897.
P berolinensis (ASCH.et GRAEBN.)GRAEBN.,Naturwiss. Wochenschr. 22(6): 361. 1907. ("Berolinensis")
24 x 26. P. xsalicifo/ius WOLFG.in SCHULT.
et SCHULT.
f., Mant. 3: 355. 1827, pro sp.
[= P lucens x P perfoliatus]
= P xdecipiens NOLTEex W.D.J. KOCH,Syn. Fl. Germ. Helv. ed. 2. 779. 1844.
P lucens var. decipiens (NOLTEex W.D.J. KOCH)HOOK.f., Stud. Fl. Brit. lsl. 372. 1870.
- P olivaceus 0. LANG,Flora 29(30): 472. 1846, pro syn.
= P decipiens var. affinis A. BENN.,J. Bot. 20: 184. 1882.
_ P xaffinis (A. BENN.) P. FOURNIER,Quatre Fl. Fr. 140. 1935.
= P upsaliensis TISELIUS,Bot. Not. 1884: 15. 1884.
_ P decipiens subsp. upsaliensis (TISELIUS)MAGNIN,Bull. Soc. Bot. France 43: 443. 1896.
= P. decipiens var. P. torssanderi TISELIUS,Potamog. Suec. Exs., fasc. 2: [sched.] no. 75. 1895. ("Torssandri")
_ P torssanderi (TISELIUS)DORFLER,Herb. Norm. No. 3583. 1898. ("Torssandri")
= P salignus FRYERin HIERN,Victoria Hist. Devon. 1: 129. 1906.
= P xdecipiens var. y. vollmannii G. FISCH.in E. BAUMANN,Veg. Untersees 105. 1911. ("Vollmanni")
- P vollmannii (G. FISCH.)G. FISCH.,Repert. Spec. Nov. Regni Veg. 14(385): 4. 1914, nom. inval.
("Vollmanni")
- P xsteriliformis HAGSTR.
in HOLMB.,Hartmans Handb. Skand. Fl. 1: 97. 1922, nom. nud.
= P xkupfferi A. BENN.,J. Bot. 66: 103. 1928. ("Kupfferi")
35 x 24. P. xcadburyae DANDYet G. TAYLOR,
Kew Bull. 12: 332. 1957.
[= P crispus x P lucens]
Notes
(1) P lucens is a distinct species which is easily distinguishable over most of its range. Taxonomic difficulties
appear on the southern border of its distribution.
(2) The hybrid between P gramineus and P lucens has been called either P xzizii or P xangustifolius. KAPLAN
(1997) definitively designated the type of P angustifolius and confirmed its priority.
(3) The name P salicifolius has often been misapplied to plants of P. xnitens. In particular,morphotypes called
P. torssanderi lead to some confusion causing some authors to assume even triple hybrids among P gramineus,
P. lucens, and P perfoliatus.
(4) P decipiens has often been wrongly considered to be a result of hybridization of P lucens x P praelongus.
The last named hybrid has never been confirmed, even though it was also proposed under various other names.
(5) Recently described species P. xinganensis Y.C. MA, Acta Sci. Nat. Univ. Intramongolicae 20(2): 281. 1989,
might represent another hybrid of P lucens.
25. Potamogeton gramineus Linnaeus, Sp. PI. 127. 1753.
= P heterophyllus SCHREB.,Spicil. Fl. Lips. 21. 1771.
Spirillus heterophyllus (SCHREB.)NIEUWL.,Amer. Midl. Naturalist 3: 17. 1913.
P gramineus subsp. heterophyllus (SCHREB.)SCHINZet THELL.,Fl. Schweiz ed. 3. 2: 16. 1914.
= P hybridus PETAGNA,Inst. Bot. 2: 289. 1787.
= P gramineus subsp. hybridus (PETAGNA)ARCANG.,Comp. Fl. Ital. 642. 1882.
PI.
276
G. Wiegleb & Z. Kaplan
= P augustanusBALB., MWm.Acad. Sci. Turin, Sci. Phys. Math. 1, 10-11 (1802-1803): 330. 1804.
("Augustanum")
= P distachyusBELLARDI, MWm.Acad. Sci. Turin,Sci. Phys. Math. 1, 10-11 (1802-1803): 447. 1804.
("distachyum")
= P lanceolatusPOIR. in LAM., Encycl.Meth. Bot., Suppl.4: 536. 1816,nom. illeg. ("lanceolatum"),
non SM.
1809.
P lanciformisROEM. et SCHULT.,Syst. Veg. ed. 16. 3: 512. 1818.
- P paucifolius OPIZ,Boheims Phaner. Crypt. Gewachse 23. 1823, nom. nud.
-
P paucifolius OPIZ,Naturalientausch 223. 1824.
P gracilis WOLFG.in SCHULT.et SCHULT.f., Mant. 3: 355. 1827.
P wolfgangiiKIHLM. in A. T. SAELAN,
KIHLM. et HJELT, Herb.Mus. Fenn.ed. 2. 1: 128. 1889, nom.
illeg. ("Wolfgangii")
P gramineusproleswolfgangii[KIHLM.] GRAEBN. inENGL.,Pflanzenr.31 (IV.11):89. 1907.("Wolfgangii")
P gramineus var. cc. graminifolius FR.,Novit. Fl. Suec. ed. 2. 36. 1828.
_ P gramineus subsp. graminifolius (FR.)SCHINZet THELL., Fl. Schweiz ed. 3. 2: 15. 1914.
P graminifolius(FR.)FRYERin FRYERet A. BENN.,Potamoget. Brit. Isles 64. 1915.
P gramineus var. f. heterophyllus FR.,Novit. Fl. Suec. ed. 2. 37. 1828.
- P gramineus [var.] ("spielart")c. heterophyllus G. MEY.,Chloris Han. 520. 1836, nom. illeg., non Fr. 1828.
P. nigrescens FR., Novit. Fl. Suec. Mant. 3: 17. 1842.
- P rufescenssubsp.nigrescens(FR.)NYMAN, Consp.Fl. Eur.4: 681. 1882.
- P kochii 0. LANG, Flora 29(30): 471. 1846, nom. illeg. ("Kochii"), non F W. Schultz 1844.
P lonchitesTuCK., Amer.J. Sci. Arts,ser.2, 6: 226. 1848.
- P heterophyllus subsp. lonchites (TUCK.)HOOK.f., Stud. Fl. Brit. Isi. 371. 1870. ("lonchitis")
- Spirilluslonchites(TUCK.)NIEUWL.,Amer.Midl.Naturalist3: 16. 1913.
P latifolius SLOBODA,Rostlinictvf 229. 1852.
- P gramineusvar.myriophyllus
J.W.ROBBINSin A. GRAY,ManualBot. North.U. S. ed. 5. 487. 1867.
= P gramineus var.maximus MORONGex A. BENN., J. Bot. 19: 241. 1881.
= P variansMORONG
ex FRYER,J. Bot. 25: 308. 1887.
= P falcatus FRYER, J. Bot. 27: 65, t. 286. 1889.
-P gramineusvar.mongolicusMAXIM.ex A. BENN., J. Bot. 28: 300. 1890, pro syn.; MAXIM.
ex A. BENN.,
-
-
Bull. Herb. Boissier 4: 546. 1896, pro syn.
? P xseemenii ASCH.et GRAEBN.,Synops. Mitteleur.Fl. 1: 335. 1897, pro hybr.P gramineus x P polygonifolius.
("Seemenii")
P biformis HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 247. 1916.
? P sarmaticus MAEMETS,Novosti Sist. Vyssh. Rast. 15: 4. 1979. ("1978")
P biformoides PAPCHENKOV,
Bot. Zhurn. 82(12): 69. 1997.
Description
Rhizome slender, rarely filiform, terete, perennial, with apical winter buds. Stem sometimes sparingly to mostly
richly branched, filiform to slender, terete, annual; specialized dormant turions not developing. Submerged
leaves sessile, linear-oblong or narrowly oblong to oblong or oblanceolate, sometimes that of the lowest leaves
reduced to phyllodes, (17-)35-90(-170) mm long, (2-)5-12(-17) mm wide, 4-12(-15) times as long as wide,
bright green to dark green, (3-)7-9(-13)-veined, with or without narrow rows of lacunae bordering the midrib,
denticulate at margins, cuneate at base, mucronate at apex. Intermediate leaves sometimes present, often as
membranous petiolate leaves. Floating leaves present or absent, petiolate; lamina broadly oblong to elliptical
or obovate-elliptical, 15-70(-95) mm long, (5-)8-34 mm wide, 1.3-3.6 times as long as wide, opaque,
coriaceous, yellow-green to dark green, (7-)1 1-21 (-23)-veined, cuneate to subcordate at base, obtuse to acute
at apex; petiole (7-)18-60(-172) mm long, 0.5-4.0 times as long as the lamina. Stipules axillary, convolute,
(6-)10-25(-35) mm long, translucent to opaque, persistent. Peduncles (20-)35-100(-350) mm long, usually
thicker than the stem, 2-6(-9) times as long as the fruiting spike. Spikes cylindrical, 15-40 mm long in fruit,
contiguous. Flowers numerous, with (3-)4(-5) carpels. Fruits 2.4-3.1 mm long, dorsal keel distinct.
Stem anatomy
Stele of oblong type, endodermis of U-type, interlacunar bundles present, in 1 outer circle, multicellular,
subepidermal bundles present or absent, pseudohypodermis absent or present, 1-layered.
Taxonomy of Potamogeton
277
Distribution
Circumpolar, boreal and temperate regions throughout the Northern Hemisphere.
Hybrids
25 x 1. P. xianceolatifolius(TISELIUS)C.D. PRESTON,
Watsonia 16(4): 437. 1987.
[= P. gramineus x P. polygonifolius]
3 x 25. P. xbillupsii FRYER,J. Bot. 31: 353, t. 337 et 338. 1893. ("Billupsii")
[= P coloratus x P gramineus]
13 x 25. P. xnericius HAGSTR.,Kungi. Svenska Vetenskapsakad. Handl. 55(5): 145. 1916.
[= P. alpinus x P. gramineus]
25 x 16. P. xsparganiifolius LAEST.ex FR., Novit. Fl. Suec. Mant. 1: 9.1832. ("sparganifolius")
[= P gramineus x P. natans]
25 x 22. P. xdeminutus HAGSTR.,Kungi. Svenska Vetenskapsakad. Handl. 55(5): 209. 1916.
[= P gramineus x P illinoensis]
25 x 24. P. xangustifolius J. PRESLin BERCHT.
et J. PRESL,Rostlinar 1, fasc. Zabnjkowite 19. 1821, pro sp.
[= P gramineus x P lucens]
25 x 26. P. xnitens WEBER,Suppi. Fl. Holsat. 5. 1787.
[= P gramineus x P. perfoliatus]
_ P heterophyllus
subsp. nitens (WEBER) HOOK. f., Stud. Fl. Brit. Isl. 371. 1870.
= P curvifolius HARTM., Handb. Skand. Fl. 78. 1820.
P nitens
=
=
=
P xlundii
P nipponicus
P nitens
-P
=
=
P. curvifolius
var.
MAKINO,
f. involutus
xinvolutus
P xfallax
Ill. Fl. Japan
ASCH. et GRAEBN.,
HAGSTR.,
P. xbiwaensis
1(9):
2, t. 56.
Mitteleur.
Synops.
Kungl.
Mag.
1896.
Man.
Fl. 1: 330.
1897.
Brit. Bot.
Fl. ed. 2. 1: 504.
Vetenskapsakad.
(Tokyo)
("involuta")
in BAB.,
Mitteleur.
Svenska
MIKI, Bot.
1879.
1891.
34: 1, t. 353 et 354.
Synops.
Fl. ed. 11. 433.
Skand.
("Lundii")
H. GROVES et J. GROVES
ASCH. et GRAEBN.,
P xfischeri
C. HARTM., Handb.
1: 13. 1890.
FRYER, J. Bot.
(FRYER)
= ? P xsubnitens
25 x 37.
(HARTM.)
K. RICHT., P1. Eur.
48: 326.
Handi.
1913.
55(5):
ed. 9. 440.
1904.
("Fischeri")
259.
1916.
1934.
[= P gramineus x P maackianus]
Notes
(1) P gramineus
great
number
is another
(2) P. sarmaticus
also been
is most
described
from
(3) No separate
taxonomic
an independent
crossing
and
Asia,
extremely
of hybridizations
which
has
polymorphic
in which
probably
a large-leaved
Scandinavia
value
form
and North
described
Delimitation
is particularly
difficult
of the
because
for P nipponicus.
with
as
of P gramineus.
Plants
of comparable
size
have
the type result
from
leaf
America.
is acknowledged
of P gramineus
been
species.
it is involved.
the small
a separate
leaved
species
The differences
form
under
from
of P perfoliatus
various
names
which
(e.g.
P
occurs
in East
sachalinensis,
P juzepczukii).
26. Potamogeton perfoliatus Linnaeus, Sp. PI. 126. 1753.
Spirillus
-
=P
perfoliatus
P. perfoliatus
loeselii
P
(L.) NIEUWL.,
var. typicus
OGDEN,
ROEM. et SCHULT., Syst.
perfoliatus
[subsp.]
Amer.
Veg.
P. loeselii
Midl.
Rhodora
ed.
45:
Naturalist
3: 17. 1913.
177.
1943,
nom.
16. 3: 508.
1818.
("Loeselii")
(ROEM. et SCHULT.) SCHUBL.
inval.
et G. MARTENS,
Fl. Wurttemb.
110.
1834.
("Loeselii")
=P
=P
-
perfoliatus
var. a. ovatifolius
perfoliatus
var. P. rotundifolius
[var.] oc. ovalifolius
P. perfoliatus
Bohm.
1838,
-
2(1):
nom.
P perfoliatus
Fl. Bohm.
1838.
251.
illeg.,
1838;
WALLR.,
MERT. et W.D.J.
non WALLR.
251.
1838;
("cordato-lanceolatus")
Sched.
MERT. et W.D.J.
Crit.
1: 66.
Crit.
1822.
1: 67.
1822.
KOCH ex FIEBER in BERCHT. et OPIZ, Oekon.-Techn.
KOCH ex FIEBER in BERCHT. et FIEBER, Potam.
Bohmens
Fl.
14.
1822.
[var.] f. cordatolanceolatus
2(1):
Sched.
WALLR.,
MERT. et W.D.J.
MERT. et W.D.J.
KOCH ex FIEBER
in BERCHT. et OPIZ, Oekon-.Techn.
KOCH ex FIEBER in BERCHT. et FIEBER, Potam.
Bohmens
14.
278
G. Wiegleb & Z. Kaplan
= P perfoliatus [var.] y. rotundifolius MERT.et W. D. J. KOCHex FIEBERin BERCHT.et OPIZ,Oekon.-Techn.
Fl. Bohm. 2(1): 251. 1838; MERT.et W. D. J. KoCH ex FIEBERin BERCHT.et FIEBER,Potam. Bohmens
14. 1838, nom. illeg., non WALLR.1822.
= P perfoliatus var. x. rotundifolius MERT.et W.D.J. KOCHex RCHB.,Icon. Fl. Germ. Helv. 7: 19. 1845, nom.
illeg., non WALLR.1822.
= P perfoliatus var. x. rotundifolius SONDER,Fl. Hambug. 98. 1850. ("1851"), nom. illeg., non WALLR.1822.
= P. perfoliatus var. muelleri A. BENN.,J. Bot. 25: 177. 1887. ("Muelleri")
P.perfoliatus subsp. muelleri (A. BENN.)GRAEBN.in ENGL.,Pflanzenr. 31 (IV.11): 95. 1907. ("Muelleri")
= P. perfoliatus var. mandschuriensis A. BENN.,Annuaire Conserv. Jard. Bot. Geneve 9: 100. 1905.
- P alatofructus A. BENN.,Trans. & Proc. Bot. Soc. Edinburgh 29(1): 49. 1924.
= P bupleuroides FERNALD,Rhodora 10: 46. 1908; FERNALDin B.L. ROBINSONet FERNALD,Gray's New
Manual ed. 7. 75. 1908.
P perfoliatus subsp. bupleuroides (FERNALD)HULTEN,Kungl. Svenska Vetenskapsakad. Hand]., ser. 4,
8(5) [Circump. P1. 1]: 254. 1964.
= P perfoliatus var. sachalinensis H. Liv., Repert. Spec. Nov. Regni Veg. 8: 285. 1910.
P sachalinensis (H. LEv.) H. LEv., Repert. Spec. Nov. Regni Veg. 10: 441. 1912.
= P juzepczukii P DOROF.et TZVELEV,Novosti Sist. Vyssh. Rast. 20: 4. 1983.
Description
Rhizome slender, terete, perennial, with apical winter buds. Stem unbranchedto richly branched, slender, terete,
annual; specialized dormant turions not developing. Submerged leaves sessile, narrowly lanceolate to broadly
ovate or orbicular-ovate, 16-115 mm long, 7-42 mm wide, (1.0-)1.3-7.0(-10.0)
times as long as wide,
yellow-green or bright green to dark green, sometimes with a reddish tinge, (7-)11-25-veined, with narrow
rows of lacunae bordering the midrib, denticulate at margins, amplexicaul at base, obtuse to acute and often
slightly hooded at apex. Floating leaves always absent. Stipules axillary, convolute, 3-22 mm long, translucent,
decaying early. Peduncles 20-110 mm long, 1-5 times as long as the fruiting spike, as thick as or slightly
thicker than the stem. Spikes cylindrical, 13-25 mm long in fruit, contiguous. Flowers (6-)9-20, with 4 carpels.
Fruits 2.2-3.5(-4.0) mm long, dorsal keel indistinct.
Stem anatomy
Stele of trio (2) type, with the trio bundle in central position, or rarely of oblong type, endodermis of 0-type,
cell wall thickening indistinct or almost absent, interlacunarbundles absent, subepidermal bundles absent or
scattered uni-cellular ones present, pseudohypodermis absent or partly present, I-layered.
Distribution
Europe, N and C Africa, Asia, Australia, E North and C America.
Hybrids
13 x 26. P. xprussicus HAGSTR.,
Bot. Not. 1908: 103. 1908.
[= P alpinus x P perfoliatus]
26 x 21. P. xanguillanus KOIDZ.,
Bot. Mag. (Tokyo) 43: 398. 1929.
[= P perfoliatus x P wrightii]
24 x 26. P xsalicifolius WOLFG.in SCHULT.
et SCHULT.
f., Mant. 3: 355. 1827, pro sp.
[= P lucens x P perfoliatus]
? 26 x 23. P. xvaginans (BOJERex A. BENN.)HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5):
280. 1916, pro sp.
[= ? P perfoliatus x P schweinfurthii]
25 x 26. P xnitens WEBER,Suppi. Fl. Holsat. 5. 1787.
[= P gramineus x P perfoliatus]
26 x 28. P. xcognatus ASCH.et GRAEBN.,
Synops. Mitteleur. Fl. 1: 317. 1897.
[= P perfoliatus x P praelongus]
- P xintermixtus A. BENN.,J. Bot. 41: 166. 1903.
35 X 26. P. xcooperi (FRYER)FRYER,Bot. Exch. Club Brit. Isles Rep. 1: 497. 1897; (FRYER)FRYER,J. Bot.
35: 311. 1897. ("Cooperi")
[= P. crispus x P perfoliatus]
P undulatus var. cooperi FRYER,J. Bot. 29: 289, t. 313. 1891. ("Cooperi")
Taxonomy of Potamogeton
279
P. xcymatodesAsCH. et GRAEBN.,
Synops.Mitteleur.Fl. 1: 337. 1897,nom. illeg.
= ? P xcymbifolius G. FISCH.,Mitt. Bayer.Bot. Ges. 1(31):366. 1904.
37 x 26. P. xleptocephalus KOIDZ.
in Y. DoI, Fl. Satsum. 2: 162. 1931.
[= P maackianus x P perfoliatus]
- P nakamurai YAMAUCHI
et MoMIY., Rep. Faun.Fl. LakeKasumigaura
7. 1971, nom. nud.
26 x 48. P. xmysticus MORONG,
Bot. Gaz. (Crawfordsville) 5: 50. 1880, pro sp.
[= P. perfoliatus x P pusillus]
Note
(1) P.juzepczukii,like otherP. perfoliatus-forms
fromEastAsia, shows certaindeviantcharactersbutin total
morphologicaldelimitationis indistinct.
27. Potamogeton richardsonii (A. BENNETT)RYDBERG,Bull. Torrey Bot. Club 32: 599. 1905.
("Richardsonii")
P.perfoliatus var.lanceolatus J.W. ROBBINSin A. GRAY,ManualBot. North.U. S. ed. 5. 488. 1867,nom.
illeg., non BLYTT1861.
P perfoliatus var.richardsonii A. BENN.,J. Bot. 27: 25. 1889. ("Richardsonii")
P perfoliatus proles loeselii var. cordatolanceolatus subvar. richardsonii (A. BENN.)ASCH.et GRAEBN.,
Synops.Mitteleur.Fl. 1: 314. 1897.
-
Spirillus perfoliatus var. richardsonii (A. BENN.)NIEUWL.,Amer. Midl. Naturalist 3: 17. 1913.
P perfoliatus subsp. richardsonii (A. BENN.)HULTEN,Fl. Alaska Yukon 1: 102. 1941.
P perfoliatus subsp. richardsonii (A. BENN.)E. MURRAY,Kalmia 12: 23. 1982. [isonymum]
Description
Rhizomeslender,terete,perennial,withapicalwinterbuds.Stemsparinglyto richlybranched,slender,annual;
specializeddormantturionsnot developing.Submergedleavessessile,narrowlylanceolateto ovate-lanceolate,
(15-)30-100 mm long, 5-19 mm wide, 2.5-7.0 times as long as wide, yellow-green to dark green,
(7-) l 3-25(-33)-veined, withnarrowrowsof lacunaeborderingthemidrib,denticulateat margins,amplexicaul
at base, narrowlyobtuse to acute but not hoodedat apex. Floatingleaves always absent.Stipulesaxillary,
convolute, 8-26 mm long, opaque, fibrous, decaying but remaining as whitish fibres. Peduncles
(14-)20-100(-250) mm long, 0.9-6.0 times as long as the fruitingspike,as thickas or slightlythickerthan
the stem. Spikes cylindrical,8-30(-40) mm long in fruit,contiguous.Flowers7-17, with 4 carpels.Fruits
2.7-4.2 mm long, dorsalkeel indistinct.
Stem anatomy
Stele of triotype,withthe triobundlesin centralposition,endodermisof 0-type, cell wall thickeningindistinct
or almostabsent,interlacunar
absentorpartly
bundlesabsent,subepidermal
bundlesabsent,pseudohypodermis
1-layered.
Distribution
NorthAmerica.
Note
(1) P richardsoniiis closely relatedto P perfoliatus.They arepartlyvicariantin theirdistribution.
28. Potamogeton praelongus WULFEN
in ROEMER,
Arch. Bot. 3(3): 331. 1805.
E P acuminatusWAHLENB.,
Fl. Upsal.58. 1820, nom. illeg. ("acuminatum")
= P lucens [var.]("spielart")
a. corniculatusG. MEY.,ChlorisHan.522. 1836.
= Spirillus praelongus (WULFEN)NIEUWL.,Amer.Midl. Naturalist3: 17. 1913.
= P flexuosus WREDOW,Oekon.-Techn.Fl. Meklenb.1: 255. 1811.
= P perfoliatus var.lacustris WALLMANin LILJ.,UtkastSv. Fl. ed. 3. 706. 1816.
= P gramineusvar.a. borealisLAEST.,Kongl.SvenskaVetenskapsakad.
Handl.1824: 162. 1824. ("boreale")
= P praelongus var.brevifolius CELAK.,Sitzungsber.Konigl.Bohm. Ges. Wiss. Prag,Math.-Naturwiss.
Cl.
1886: 11. 1886.
= P praelongus var.6. angustifolius GRAEBN.in ENGL.,Pflanzenr.31 (IV.11): 97. 1907.
= P praelongus f. pygmeus GALINISin NATKEVICAITE-IVANAUSKIENE,
Liet. TSR Flora 2: 677. 1963.
280
G. Wiegleb & Z. Kaplan
Description
Rhizomeslenderor robust,terete,perennial,with apical winterbuds and overwinteringshortshoots. Stem
unbranched
to richlybranched,slenderto robust,terete,annualto perennial;winterbudsas axillary,short,leafy
shoots, specialized dormantturions not developing. Submergedleaves sessile, narrowlylanceolate to
lanceolate-ovate,(45-)60-180(-360) mm long, 14-40 mm wide, (2.5-)3.0-7.5(-l 1.0) timesas long as wide,
brightgreento darkgreen, 11-19(-25)-veined, with narrowrows of lacunaeborderingthe midrib,entireat
margins,roundedand semiamplexicaulat base, obtuseanddistinctlyhoodedat apex. Floatingleaves always
absent.Stipulesaxillary,convolute, 10-80 mm long, translucentwhen fresh, opaquewhen dry, persistent.
Peduncles(50-)80-250(-800) mmlong, 2-7(-9) timesas long as the fruitingspike,as thickas or thickerthan
the stem.Spikescylindrical,20-80 mmlong in fruit,contiguous.Flowersnumerous,with(2-)4 carpels.Fruits
(3.8-)4.5-5.5 mm long, dorsalkeel distinct.
Stem anatomy
Stele of prototype, endodermisof U-type,rarely0-type, interlacunar
bundlespresent,in 2-3 circles,strong,
subepidermal
bundlespresent,pseudohypodermis
present,1-3-layered.
Distribution
Circumboreal,
throughoutthe northernhemisphere.
Hybrids
13 x 28. P. xgriffithiiA. BENN.,J. Bot. 21: 65, t. 235. 1883. ("Griffithii")
[= P. alpinus x P praelongus]
26 x 28. P. xcognatus ASCH. et GRAEBN., Synops. Mitteleur. Fl. 1: 317. 1897.
[= P perfoliatus x P praelongus]
35 x 28. P. xundulatus WOLFG. in SCHULT.et SCHULT.f., Mant. 3: 360. 1827, pro sp.
[= P crispus x P praelongus]
29. Potamogeton epihydrus RAFINESQUE,Med. Repos., Hexade 3, 2: 409.1811.. ("epihydrum")
- P epihydrus var.typicus FERNALD, Mem.Amer.Acad.ArtsSci. 17(1): 114. 1932, nom. inval.
- P epihydrusRAF.,Med. Repos.,Hexade2, 5: 354. 1808, nom. prov.("epihydrum")
= P. nuttallii CHAM.et SCHLTDL., Linnaea2(2): 226, t. 6, fig. 25. 1827. ("Nuttalii")
-P. epihydrus var.nuttallii (CHAM. et SCHLTDL.) FERNALD, Mem.Amer.Acad.ArtsSci. 17(1): 115. 1932.
= P epihydrussubsp. nuttallii(CHAM.et SCHLTDL.) CALDER et R.L. TAYLOR, Canad.J. Bot. 43: 1388.
1965.
= P pennsylvanicusWILLD. ex CHAM.et SCHLTDL., Linnaea2(2): 227. 1827. ("pensylvanicus")
= P pumilus WOLFG. in SCHULT. et SCHULT. f., Mant.3: 354. 1827.
= P claytonii TUCK., Amer.J. Sci. Arts,ser. 1, 45: 38. 1843. ("Claytoni")
= P nuttallii var.ramosus PECK, AnnualRep. New YorkStateMus. 47: 162. 1894.
= P epihydrus var. ramosus (PECK) H.D. HOUSE,New York State Mus. Bull. 254: 52. 1924.
= P nuttallii var.cayugensis WIEGAND, Rhodora2: 102. 1900. ("Cayugensis")
-P epihydrus var.cayugensis (WIEGAND) A. BENN., J. Bot. 42: 69. 1904. ("Cayugensis")
=P cayugensis(WIEGAND)HAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5): 140. 1906.
= P tennesseensis FERNALD, Rhodora38: 167. 1936.
Description
Rhizomeslenderto robust,compressed,perennial,withapicalscalywinterbuds.Stemunbranched
or sparingly
branched,slenderto robust,compressedto teretetowardsthe apex, annual;specializeddormantturionsnot
developing.Submergedleaves sessile, often markedlydistichous,linearto ribbon-like,65-240 mm long,
(1.0-)2.5-1 1.0 mm wide, 18-30(-60) times as long as wide, brightgreen to olive green or brown-green,
sometimeswitha reddishorbrownishtinge,5-9(-1 3)-veined,withbroadrowsof lacunaeborderingtheniidrib,
entireat margins,straightto narrowlycuneateat base, narrowlyobtuseto acuteat apex. Intermediate
leaves
sometimespresent,shortpetiolate;petioleoftenflattened.Floatingleavespetiolate;laminaoblongto elliptical,
35-80 mmnlong, 7-22 mm wide, 2.5-5.0 times as long as wide, opaque,coriaceous,brown-greento dark
green,9-21-veined, cuneateat base,obtuseat apex;petiolenot flattened,20-60(-90) mm long,0.5-2.0 times
as long as the lamina.Stipulesaxillary,convolute,10-45 mm long, translucent,decayingearly.Peduncles
23-90 mm long, 1.5-4.0 times as long as the fruitingspike,usuallyas thickas the stem, mostly insertedin
the axils of floating leaves, rarelyin the axils of, or suboppositeto, submergedleaves. Spikes cylindrical,
Taxonomy of Potamogeton
281
10-30 mm long in fruit, contiguous. Flowers 11-18, with 4 carpels. Fruits 2.5-3.1(-4.0) mm long, dorsal keel
indistinct.
Stem anatomy
Stele of eight bundles or oblong to four bundles type, endodermis of 0-type, interlacunar bundles absent or
scattered ones present, subepidermal bundles absent or scattered ones present, pseudohypodermis absent.
Distribution
North America, NW Europe (British Isles).
30. Potamogeton ulei K. SCHUMANN
in MARTIUS,
Fl. Bras. 3(3): 690. 1894. ("Ulei")
= ? P sclerocarpus K. SCHUM.in MART.,Fl. Bras. 3(3): 688. t. 120, fig. 2. 1894.
= P paramoanusR.R. HAYNESet HOLM-NIELS.,
Syst. Bot. 7(4): 498. 1982.
Description
Rhizome slender, compressed, perennial, with apical winter buds. Stem unbranched, slender, terete to slightly
compressed, annual; specialized dormant turions not developing. Submerged leaves sessile, linear, 35-265 mm
long, 1.0-4.1 mm wide, 25-70 times as long as wide, bright green to olive green or brown-green, sometimes
with a reddish or brownish tinge, 3-7-veined, with broad rows of lacunae bordering the midrib, entire at
margins, straight at base, narrowly obtuse to acute at apex. Intermediate leaves often present. Floating leaves
mostly present, petiolate; lamina oblong to elliptical, 14-31 mm long, 6-9 mm wide, 2-4 times as long as
wide, opaque, coriaceous, brown-green to dark green, 5-9-veined, narrowly cuneate at base, acute to obtuse
at apex; petiole 14-44 mm long, 0.8-1.5 times as long as the lamina, mostly flattened. Stipules axillary,
convolute, 5-26 mm long, translucent, decaying early. Peduncles 11-27 mm long, 1.5-2.5 times as long as
the fruiting spike, as thick as or thinner than the stem, inserted in the axils of both floating and submerged
leaves. Spikes cylindrical, 6-14 mm long in flower, contiguous. Flowers 12-18, with 4 carpels. Fruits 2.3-2.7
mm long, dorsal keel distinct.
Stem anatomy
Stele of four bundles type, endodermis of 0-type, interlacunarbundles absent, rarely present, subepidermal
bundles present, pseudohypodermis present (1-layered?).
Distribution
N and NE South America.
Notes
(1) P ulei is closely related to P epihydrus.
(2) Since its original introduction, P ulei has always been considered as a homophyllous species similar to
P polygonus. However, the leaf anatomy of the original collection ULE 1919 (HBG), with their well developed
lacunae and abundantanastomoses, clearly points these plants to the P epihydrus-group.In addition, isolectotype
plants have well developed floating leaves, by which character they are definitively distinguished from
P polygonus.
(3) P sclerocarpus shows certain deviating characters in its general appearance and stem anatomy. We are
inclined to presume that such named plants represent deep-water forms of P ulei, since both the morphotypes
share many important distinguishing characters, especially in leaf anatomy.
31. Potamogeton montevidensis A. BENNETT,
Ann. K. K. Naturhist. Hofmus. Wien 7(4): 293.
1892.
Description
Rhizome slender, terete, perennial, non-dormant scaly winterbuds present. Stem unbranched, slender, terete,
annual;specialized dormantturions not developing. Submerged leaves sessile; lamina linear-lanceolate to linear,
mostly decaying early, 70-100 mm long, 4-6 mm wide, 14-21 times as long as wide, bright green to
brown-green, 5-9-veined, with broad rows of lacunae bordering the midrib, entire at margins, straight to
narrowly cuneate at base, acute at apex. Intermediaiteleaives sometimes present, petiolate, lanceolate. Floating
leaves petiolate; lamina oblong or lanccolate to obovate, 33-50(-65) mm long, (5-)15-20(-25) mm wide,
2.1-4.5(-6.6) times as long as wide, opaque, corialceOus, bright green to brown-green, 11-15(-17)-veined,
cuneate at base, rounded or subacute at apex; petiole flattened, 40-115(-150) mm long, 1.1-2.5 times as long
as the lamina. Stipules axillary, convolute, 20-35 mm long, translucent,decaying early. Peduncles 40-100 mm
282
G. Wiegleb & Z. Kaplan
long, 2-5 timesas long as the fruitingspike,as thickas or slightlythinnerthanthe stem,insertedas lateralor
terminalin the axils of floatingleaves, or rarelysuboppositeto floatingleaves. Spikescylindrical,10-30 mm
long in fruit,contiguous.Flowers 1-13, with4 carpels.Fruits3.0-3.5 mm long, dorsalkeel distinct.
Stem anatomy
Stele of trioor complex4 bundlestype, endodermisof 0-type or faintU-type,interlacunar
bundlesabsentor
1 circlepresent,subepidermalbundlespresentas incompletecircle,pseudohypodermis
absent.
Distribution
Argentina,Uruguay,Brazil.
Note
(1) P. montevidensisis closely relatedto P. epihydrusand to P ulei. Delimitationis indistinctdespitethe
geographicaldistance.
32. Potamogeton drummondiiBENTHAM
in BENTHAM
et F. MUELLER,
Fl. Austral. 7: 171. 1878.
("Drummondii")
= ? P similisA. BENN.,J. Bot. 40: 146. 1902.
Description
Rhizomefiliformto slender,terete,perennial,winterbudsnot seen. Stemunbranched,
slender,terete,annual;
specializeddormantturionsnot developing.Submergedleaves sessile to shortlypetiolate;laminanarrowly
oblong to lanceolateor broadlyovate, 40-120 mm long, 5-20 mm wide, 2-12 times as long as wide, pale
green,3-1 1-veined,withnarrowrowsof lacunaeborderingthemidrib,entireat margins,cuneateatbase,acute
at apex;petiole0-5 mm long, 0-0.05 timesas long as the lamina.Floatingleavespresentor absent,petiolate;
laminaellipticalto broadlyelliptical,20-40 mm long, 12-25 mm wide, 1.2-2.0 timesas long as wide,opaque,
coriaceous,yellow-greento olive green,9-15-veined,broadlycuneateatbase,acuteatapex;petiole(10-)35-80
mm long, (0.3-)1.0-2.4 times as long as the lamina.Stipulesaxillary,convolute,16-25 mm long, translucent,
persistent.Peduncles30-90 mm long, 4-6 times as long as the fruitingspike, slightlythickerthanthe stem,
insertedin the axils of floatingandsubmergedleaves.Spikessubgloboseto cylindrical,7-22 mm long in fruit,
contiguous.Flowers 10-16, with 4 carpels.Fruits1.7-2.0(-2.5) mm long, dorsalkeel distinct,lateralkeels
indistinct.
Stem anatomy
Stele mostlyof fourbundlestype, sometimesof protoor triotype,endodermisof 0-type, interlacunar
bundles
absent or present in 1 incompletecircle, subepidermalbundlesusually absent, rarelyfaint ones present,
pseudohypodermis
absentor partlypresent.
Distribution
Westemand SouthernAustralia,Tasmania.
Note
(1) P. drummondiiis not sufficientlyknown as to the rangeof its characters.It is eitheranotherextremely
polymorphicspecies or it consists of two independenttaxa.The "holotype"Drummond,Nova Hollandia,is
of uncertainorigin, and has relativelywell-developedsubepidermalbundles.RAUNKIAER(1903) found no
such bundles,only single strands,althoughHAGSTROM
(1916) did. In the specimeninvestigated(fromC) it
wasdifficultto decidewhatone can reallysee. Therearesomebundlesbutwhethertheyaretrulysubepidermal
or the outerinterlacunar
ones cannotbe discerned.The presentdescriptionis basedon recentspecimensonly
(Weston80-44, PERTH;Gardner1372, PERTH;Orchard4356, PERTH;Strid21233, B, C, PERTH;Strid
21234, B, C, M; Meebold2/27, M). Withinthese specimenstwo morphotypesexist, one with lanceolateand
one with oblong submergedleaves. The oblongmorphotypealways lacks subepidermal
bundles.Cultivation
experimentsare necessaryto clarifythe statusof the morphotypes.
33. Potamogeton cheesemanii A. BENNETT,
J. Bot. 21: 66. 1883. ("Cheesemanii")
- P oblongifoliusKIRKex HOOK.
f., Handb.New Zeal. Fl. 2: 742. 1867, nom. nud.
- P. natansvar.australisKIRKex A. BENN.,J. Bot. 25: 177. 1887, pro syn.; KIRK
ex A. BENN.,Ann. K. K.
Naturhist.Hofmus.Wien7: 286. 1892,pro syn.
= ? P tricarinatusF. MUELL.
et A. BENN.,J. Bot. 30: 229. 1892.
= ? P samariformis HAGSTR.,Kungl.SvenskaVetenskapsakad.
HandI.55(5): 166. 1916.
283
Taxonomy of Potamogeton
=
=
=
=
? P sessilifolius HAGSTR.,
Handl.55(5): 167. 1916.
Kungl.SvenskaVetenskapsakad.
P porrigens HAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 172. 1916.
Handl.55(5): 174. 1916.
P cheesemanii f. tasmanicus HAGSTR.,Kungl.SvenskaVetenskapsakad.
? P. cheesemanii f.frondosus HAGSTR.,
Handl.55(5): 174. 1916.
Kungl.SvenskaVetenskapsakad.
Description
Rhizomefiliformto slender,terete,perenial,winterbudsnot seen. Stem unbranchedor sparinglybranched,
slender,terete,annual;specializeddormantturionsnot developing.Submergedleaves sessile or subsessileto
shortlypetiolate;laminanarrowlylinear-lanceolate
or narrowlyelliptical,relativelyuniform,40-100 mmlong,
5-15 mm wide, 6-12 times as long as wide, brightgreento darkgreen, sometimeswith a brownishtinge,
5- 1-veined, with narrowrows of lacunaeborderingthe midrib,entireat margins,narrowlycuneateat base,
roundedto emarginateor subacuteat apex;petiole0-5(-30) mm long, 0.00-0.05(-0.30) times as long as the
lamina.Intermediate
leaves sometimespresent,petiolate,lanceolateto lanceolate-spathulate;
petioleup to 20
mm long. Floatingleavespresentor absent,petiolate;laminaovateto elliptical-oblong,20-45(-58) mm long,
10-26 mm wide, 1.3-3.3 times as long as wide, opaque,coriaceous,yellow-greento olive green,sometimes
with a brownishtinge, (5-)9-1 5(-17)-veined,roundedor truncateto subcordateat base, roundedto subacute
at apex;petiole(15-)30-80 mm long, (0.3-)1.5-3.2 timesas long as the lamina.Stipulesaxillary,convolute,
(13-)24-35 mm long, translucent,decayingor persistent.Peduncles(23-)40-60 mm long, 2.5-4.0 times as
long as the fruitingspike,as thickas the stem,insertedin the axilsof floatingleaves.Spikescylindrical,10-25
mm long in fruit, contiguous.Flowers 16-numerous,with 4 carpels.Fruits2.0-2.6 mm long, dorsalkeel
distinct,lateralkeels distinct.
Stem anatomy
Stelemostlyof fourbundlestype,sometimesof protoortriotype,withstrongcentralsclerenchyma,endodermis
of 0-type, rarelyO-U-type,interlacunar
bundlesabsentor outercirclepresent,subepidermal
bundlespresent,
mostlystronglydeveloped,pseudohypodermis
absent.
Distribution
New Zealand,Australia,Tasmania.
Notes
(1) In the presenttreatmentP cheesemanii is conceivedas a species comprisinga wide rangeof divergent
morphotypes.Becauseof thispolymorphismthe wide distribution
of P cheesemanii has beenoverlookeduntil
recently.ConfusionwithP. sulcatus (underP tricarinatus), P australiensis, P drummondii, andP suboblongus
has occurred.The ultimateidentityof several synonyms(P sessilifolius, P samarifonnis, also P similis)
dependson the choice of lectotypesin the futureand the exact delimitationbetween P cheesemanii and
P drummondii. So far unrecognizedhybridization
may be anothercause of confusion.
(2) Thename"P tricarinatus" has beenappliedto almostanybroad-leavedPotamogeton speciesof Australia.
In the strictsense however,P tricarinatus may be regardedas a species in its own right.In theirtreatment
submittedto Flora of Australia,Papassotiriou,Jacobsand Hellquistprovidea shortdescription.The plant
resemblesP cheesemanii in generalhabitbut is closer to P sulcatus with respectto fruitshape.The plantis
rare,andobviouslyrarelycollectedanddistributedamongtheherbaria.At presentthereis notenoughmaterial
availableto providea fully satisfactorydescription.
34. Potamogeton solomonensis
WIEGLEB,
Blumea 37: 381. 1993.
Description
Rhizomeslender,terete,perennial,winterbudsnot seen. Stemunbranched,
slender,terete,annual;specialized
dormantturionsnot developing.Submergedleaves mostlypetiolate,sometimessubsessile;laminalanceolate
to ribbon-like,partlyfalcate,80-135(-150) mm long, 5-8(-15) mm wide, 8-19 timesas long as wide,bright
greento darkgreen,3-5-veined, withnarrowrowsof lacunaeborderingthemidrib,entireat margins,narrowly
cuneateatbase,acuteat theapex;petiole(0-)20-50 mmlong,(0-)0.2-0.4 timesas longas thelamina.Floating
leaves presentor absent,petiolate;laminaoblongto lanceolate,35-45 mm long, 12-18 mm wide, 2.3-3.1
times as long as wide, opaque,coriaceous,yellow-greento olive green, 9-1 1-veined, narrowlyto broadly
cuneateat base, obtuse to subacuteat apex; petiole 40-80 mm long, 1.7-4.0 times as long as the lamina.
Stipulesaxillary,convolute,20-30 mm long, translucent,persistent.Inflorescencesdimorphic.Peduncleof
apical inflorescencesinsertedin the axils of floatingleaves, 40-60 mm long, 2.5-4.0 times as long as the
floweringspike, as thick as the stem;peduncleof lateralinflorescencesinsertedin the axils of submerged
284
G. Wiegleb & Z. Kaplan
leaves or suboppositeto submergedleaves, 10 mm long, withthe spike6 mm long, oftenundeveloped.Spikes
dimorphic,cylidricalor subglobose,(6-)10-15 mm long in flower,contiguous.Flowersnumerous,with 4
carpels.Ripe fruitsnot seen.
Stem anatomy
Stele of reducedtrio or four bundlestype, endodermisof 0-type, interlacunar
bundlesabsent,subepidermal
bundlesabsent,pseudohypodermis
absentor present,1-layered.
Distribution
SolomonIslands,New Caledonia.
Note
(1) P solomonensis is closely related to P cheesemanii.
35. Potamogeton crispus Linnaeus, Sp. PI. 126. 1753.
- P crispus var. a. genuinus RCHB.,Icon. Fl. Germ. Helv. 7: 18. 1845, nom. inval.
- P tuberosus ROXB.,Hort. Beng. 12. 1814, nom. nud. ("tuberosum")
P tuberosus ROXB.in CAREY,Fl. Ind. 1: 472. 1820. ("tuberosum")
P serrulatusOPIZ,Flora5: 267. 1822, nom.nud.;OPIZ,BoheimsPhaner.Crypt.Gewachse23. 1823,nom.
nud.("serrulatum")
= P crenulatus D. DON, Prodr. Fl. Nepal. 22. 1825. ("crenulatum")
-
- P crispatus WALLMANex FR., Novit. Fl. Suec. ed. 2. 43. 1828, pro syn.
= P crispus [var.] ("spielart")a. planifolius G. MEY., Chloris Han. 523. 1836.
P. crispus [var.]a. acutifolius FIEBERin BERCHT.et OPIZ,Oekon.-Techn.
Fl. Bohm.2(1): 269. 1838;FIEBER
in BERCHT.et FIEBER,Potam. Bobhmens32. 1838.
= P crispus[var.]P. obtusifoliusFIEBERin BERCHT.et OPIZ,Oekon.-Techn.
Fl. Bohm. 2(1):269.1838;FIEBER
-
in BERCHT. et FIEBER, Potam. Bohmens 32. 1838.
= P crispusvar.P. gemmiferRCHB.,Icon. Fl. Germ.Helv.7: 18, t. 30, fig. 51. 1845.
= P crispus var. Y. serrulatus SCHRAD.ex RCHB.,Icon. Fl. Germ. Helv. 7: 18, t. 30, fig. 52. 1845.
= P lactucaceus MONTANDON,Guide Bot. Sundgau [= FRICHE-JOSET,
Syn. Fl. Jura ed. 2.] 305. 1868.
("lactucaceum")
= P hohenackeri GAND.,Oesterr.Bot. Z. 31: 43. 1881. ("Hohenackeri")
= P hungaricus GAND.,Oesterr. Bot. Z. 31: 43. 1881.
= P pallidior GAND.,Oesterr. Bot. Z. 31: 43. 1881.
= P rubricans GAND.,Oesterr. Bot. Z. 31: 43. 1881.
= P austriacus GAND.,Oesterr. Bot. Z. 31: 44. 1881.
= P leptophyllus GAND.,Oesterr. Bot. Z. 31: 44. 1881.
= P macrorrhynchus GAND.,Oesterr. Bot. Z. 31: 44. 1881.
_ P crispus var. macrorrhynchus (GAND.)ASCH. et GRAEBN.,Synops. Mitteleur. Fl. 1: 336. 1897.
= P notarisiiGAND.,Oesterr.Bot. Z. 31: 44. 1881. ("Notarisii")
= P rubrinaevus GAND.,Oesterr. Bot. Z. 31: 44. 1881.
Description
Rhizomefiliformto slender,compressed,annualor biennial.Stemunbranched
or sparinglybranched,filiform
to slender,compressed,bicanaliculate,annualor partlywintergreen;stiff axillarynon-dormantturionsof
variousshapesdevelopingthroughoutthe growthseason.Submergedleaves sessile, linearto linear-oblong,
25-95(-132) mm long, (4-)6-12(-18) mm wide, 5-9(-13) timesas long as wide, brightgreento darkgreen,
oftenwitha reddishtinge,(3-)5(-7)-veined, withnarrowto broadrowsof lacunaeborderingthemidrib,serrate
and usuallystronglyundulateat margins,broadlycuneateat base, obtuseto acute at apex. Floatingleaves
alwaysabsent.Stipulesaxillary,convoluteto shortlyconnate,4-12(-17) mm long,translucent,
decayingearly.
Peduncles14-65(-125) mmlong,3-8 timesas longas thefruitingspike,as thickas thestem.Spikescylindrical,
5-16 mmlong in fruit,contiguousto shortlydistant.Flowers3-8, with(2-)4 carpels.Fruits4.0-6.2 mmlong,
adnateat base,dorsalkeel distinct,beakvery prominent,0.5-0.8 timesas long as the restof the fruit.
Stem anatomy
Stele of oblong type, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundles absent,
pseudohypodermis
present,1-layered,or absent.
Taxonomy of Potamogeton
285
Distribution
Europe, Africa, Asia, Australia, introduced in New Zealand, North America and S South America.
Hybrids
13 x 35. P. xolivaceus BAAGOE ex G. FISCH.,Ber. Bayer. Bot. Ges. 11: 33. 1907.
[= P alpinus x P. crispus]
35 x 24. P. xcadburyae DANDYet G. TAYLOR,
Kew Bull. 12: 332. 1957.
[= P. crispus x P. lucens]
35 x 26. P. xcooperi (FRYER) FRYER, Bot. Exch. Club Brit. Isles Rep. 1: 497. 1897; (FRYER)FRYER,J. Bot.
35: 311. 1897. ("Cooperi")
[= P crispus x P. perfoliatus]
35 x 28. P. xundulatus WOLFG.in SCHULT.
et SCHULT.
f., Mant. 3: 360. 1827, pro sp.
[= P crispus x P praelongus]
35 x 47. P xlintonii FRYER,J. Bot. 38: 366. 1900; FRYER,Bot. Exch. Club Brit. Isles Rep. 1899-1900: 21.
1900. ("Lintoni")
[= P crispus x P friesii]
35 x 55. P. xbenneffii FRYER,J. Bot. 33: 1, t. 348. 1895. ("Bennettii")
[= P. crispus x P trichoides]
Note
(1) P crispus exhibits extreme morphological variation. Despite this fact it is always easily recognizable as
being the most distinct species within the genus.
36. Potamogeton robbinsii OAKES,Mag. Hort. Bot. 7(5): 180. 1841. ("Robbinsii")
_ Spirillus robbinsii (OAKES) NIEUWL., Amer. Midl. Naturalist 3: 19. 1913. ("Robbinsii")
- P pumilus NuTT. ex A. BENN., Ann. K. K. Naturhist. Hofmus. Wien 7: 292. 1892, pro syn. ("pumilum")
Description
Rhizome slender, terete, perennial. Stem sparingly branchedbelow, richly branchedupwards, filiform to slender,
terete, annual; axillary or apical dormant turions developing. Submerged leaves sessile, linear to lanceolate,
25-80(-120) mm long, (2-)3-6(-8) mm wide, 7-15 times as long as wide, dark green, 5-7-veined, with 20-72
additional sclerenchymatous strands, without rows of lacunae bordering the midrib, mostly serrulateat margins,
auriculate at base, acute at apex. Floating leaves always absent. Stipules adnate, convolute, 5-21 mm long,
fused with the leaves for 2-12 mm, opaque, whitish, persistent. Peduncles 30-50(-70) mm long, 2-5 times
as long as the fruiting spike, as thick as the stem. Spikes cylindrical, 5-20 mm long in fruit, contiguous to
shortly distant. Flowers 4-7, with 4 carpels. Fruits extremely rare, 3.5-4.7(-6.2) mm long, dorsal keel distinct.
Stem anatomy
Stele of complex oblong type, sometimes of proto type, endodermis of 0-type, with varying strength, scattered
interlacunarbundles present, subepidermal bundles present, pseudohypodermis present, 1-layered.
Distribution
North America.
Note
(1) P robbinsii is closely related to P maackianus.
37. Potamogeton maackianus A. BENNETT,J. Bot. 42: 74. 1904. ("Maackianus") [nom. cons.
prop.]
P serrulatusREGEL et MAACK in REGEL, MWm. Acad. Imp. Sci. Saint P6tersbourg, ser. 7, Sci. Phys.-Math..
4(4): 139. 1861.
= P robbinsii var.japonicus A. BENN.,Bull. Herb. Boissier 4: 549. 1896.
Description
Rhizome slender, terete, perennial, with wintergreen short shoots. Stem richly branched, slender, terete, annual
to perennial; specialized dormant turions not developing. Submerged leaves sessile, linear, 14-80(-100)
mm
long, (1 .1-)1.5-4.0 mm wide, 8-25 times as long as wide, bright green to olive green or dark green, 3-5-veined,
with 4-8 additional sclerenchymatous strands, with narrow rows of lacunae bordering the midrib, serrulate at
margins, rounded at base, acute at apex. Floating leaves always absent. Stipules adnate, convolute, 4-12 mm
286
G. Wiegleb & Z. Kaplan
long, fusedwith the leaves for 2-6 mm,translucentto opaque,persistent.Peduncles12-35 mm long, 1.5-5.5
times as long as the fruitingspike,as thickas the stem.Spikescylindrical,4-10 mm long in fruit,contiguous
to shortlydistant.Flowers2-4, with 4 carpels.Fruitsrare,3.3-3.8 mm long, dorsalkeel distinct.
Stem anatomy
Stele of oblong type, endodermisof 0-type, interlacunarbundles absent, subepidermalbundles present,
pseudohypodermis
1-layered.
Distribution
E andSE Asia.
Hybrids
37 x 21. P. xphilippinensis A. BENN.,Philipp.J. Sci. 9: 342. 1914.
[= P. maackianusx P wrightii]
25 x 37. P. xbiwaensis MIKI,
Bot. Mag.(Tokyo)48: 326. 1934.
[= P gramineusx P. maackianus]
37 x 26. P. xleptocephalus KOIDZ.in Y. Doi, Fl. Satsum. 2: 162. 1931.
[= P maackianusx P perfoliatus]
37 x 46. P. xkyushuensis KADONO
et WIEGLEB,
J. Jap. Bot. 62(3): 76. 1987.
[- P maackianusx P oxyphyllus]
= P tenuinervisA. CAMUSin LECOMTE, Not. Syst. 1: 88. 1909, p. p.
Notes
(1) P. serrulatusREGEL et MAACK,the earliestnamerelatingto the speciesconcerned,has beenfoundnot to
be illegitimateas formerlysupposed.However,for reasonsof preservingnomenclatural
stabilityandin order
to avoid a disadvantageous
nomenclatural
changeit is proposedto conservethe widely andpersistentlyused
name,P maackianus(KAPLAN 1998).
(2) Thetypecollectionof P tenuinervisconsistsof plantsof bothP.maackianusandP xkyushuensis.
Selection
of a single lectotypewill be necessaryin the future.
38. Potamogeton polygonus CHAMISSO
et SCHLECHTENDAL,
Linnaea 2(2): 184, t. 4, fig. 1 1. 1827.
= ? P. pseudopolygonusHAGSTR., Kungl.SvenskaVetenskapsakad.
Handl.55(5): 81. 1916.
Description
Rhizomefiliformto slender,terete,perennial.Stem richlybranched,filiformto slender,compressed,annual;
axillaryor apical dormantturionsdeveloping.Submergedleaves sessile, linearto linear-lanceolate,
90-170
mm long, 3-6(-9) mm wide, 17-30 times as long as wide, brightgreen to dark green or olive green,
(5-)7-9-veined, with 24-36 additionalsclerenchymatous
strands,borderedby a very strongmarginalvein,
with narrowrows of lacunaeborderingthe midrib,entireat margins,narrowlycuneateat base, acuminateat
apex. Floatingleaves always absent.Stipulesaxillary,convolute, 15-30 mm long, translucentto opaque,
persistentbut erodingearly to fibrousstrandsat the apex. Peduncles15-55 mm long, 0.8-2.0 times as long
as the fruitingspike, as thick as the stem. Spikescylindrical,12-23 mm long in fruit,contiguousto shortly
distant.Flowers(6-)12-16, with 1-2 carpels.Fruits2.8-3.5 mm long, dorsalkeel distinct.
Stem anatomy
Stele of protoor reducedtrio type, endodermisof 0-type, scatteredinterlacunar
bundlespresentor absent,
subepidermal
bundlespresent,pseudohypodermis
present,1-layered.
Distribution
SouthAmerica.
Hybrids
38 x 48. P xaftenuatus HAGSTR.,
Kungi. Svenska Vetenskapsakad. Handl. 55(5): 112. 1916.
[= P polygonus x P pusillus]
Note
(1) P polygonusis superficiallysimilarto non-floatingleavedphenotypesof P ulei. However,they can be
clearlydistinguishedby thepresenceof distinctsclerenichymatous
strands,absenceof extensivelacunae,longer
internodesand reducedcarpelnumber.The morphologicalsimilarityis due to convergenceamongdistinct
speciesgroups(P epihydrus-group
vs. P compressus-group).
Taxonomy of Potamogeton
287
39. Potamogeton ochreatus RAOUL,Ann. Sci. Nat., Ser. 3, 2: 117. 1844.
Description
Rhizomeslender,terete,perennial,short.Stemrichlybranched,slender,terete,annual;lateraldormantturions
developing.Submergedleaves sessile, linear,25-90(-130) mm long, 2-5(-6) mm wide, 10-25 timesas long
as wide, brightgreen to darkgreen, sometimeswith a brownishtinge, (3-)5-veined, with 20-32 additional
sclerenchymatous
strands,borderedby a strongmarginalvein, with narrowrows of lacunaeborderingthe
midrib,entireat margins,narrowlycuneateat base, obtuseat apex. Floatingleaves always absent.Stipules
axillary,convolute,4-15(-20) mm long, translucentto opaque,persistentbuterodingearlyto fibrousstrands
at the apex. Peduncles(20-)30-75 mm long, 2-4 times as long as the fruitingspike, as thick as the stem.
Spikescylindrical,9-15 mm long in fruit,contiguous.Flowers6-9, with4 carpels.Fruits2.8-4.5 mm long,
dorsalkeel distinctto indistinct.
Stem anatomy
Stele of oblong type, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundlespresent,
pseudohypodermis
present,2-3-layered.
Distribution
SW, S, SE andE Australia,New Zealand.
40. Potamogeton furcatus HAGSTROM,
Kungi. Svenska Vetenskapsakad. Handl. 55(5): 80. 1916.
Description
Rhizomefiliformto slender,terete,perennial,short.Stemrichlybranched,terete,slender,annual;specialized
dormantturionsnot seen. Submergedleaves sessile, linear,85-140(-200) mm long, 2-4 mm wide, 25-50
timesas long as wide, brightgreento darkgreen,sometimeswitha brownishtinge,(3-)5-veined,with20-32
additionalscierenchymatous
strands,borderedby a strongmarginalvein,withnarrowrowsof lacunaebordering
the midrib,entireat margins,narrowlycuneateat base, acuteat apex.Floatingleaves alwaysabsent.Stipules
axillary,convolute,8-15 mm long, translucentto opaque,persistentbuterodingearlyto fibrousstrandsat the
apex. Peduncles 10-24 mm long, 1-3 times as long as the floweringspike, as thick as the stem. Spikes
cylindrical,8-12 mm long in flower,contiguous.Flowers8, with4 carpels.Fruitsnot seen.
Stem anatomy
Stele of oblong type, endodermisof 0-type, interlacunarbundles absent, subepidermalbundles present,
pseudohypodermis
present,2-3-layered.
Distribution
Papua-NewGuinea,New Caledonia?,SE andE? Australia.
Note
(I) P furcatusis closely relatedto P ochreatus,buthas a differentgeographicaldistribution.It has also been
informallydescribedas Potamogetonsp. A by LEACH& OSBORNE
(1985).
41. Potamogeton acutifolius LINKin ROEMER
et SCHULTES,
Syst. Veg. ed. 16. 3: 513. 1818.
P zosterifolius[var.]P. acutifolius(LINK)SCHULT.
et SCHULT.
f., Mant.3: 362. 1827.
P compressussubsp.acutifolius(LINK)HOOK.f., Stud.Fl. Brit.Isl. 373. 1870.
- P cuspidatusSCHRAD.
ex MERT.
et W.D.J.KOCH,
RohlingsDeutschl.Fl. ed. 3. 1: 854. 1823, pro syn.
-P acutifoliusvar.oc.majorFIEBER
in BERCHT.
et OPIZ,Oekon.-Techn.Fl. Bohm. 2(1): 272. 1838;FIEBER
in BERCHT.
et FIEBER,
Potam.Bohmens35. 1838.
- P. acutifoliusvar.
minor
FIEBER
in BERCHT.
et OPIZ,Oekon.-Techn.Fl. Bohm. 2(1): 272. 1838;FIEBER
P.
in BERCHT.
et FIEBER,
Potam.Bohmens35. 1838.
- ? P henningiiA. BENN.,
J. Bot. 48: 151. 1910. ("Henningii")
Description
Rhizomeabsentor filiform,compressedto almostterete,annual,short.Stem sparinglyto richly branched,
filiformto slender,stronglycompressedto flattened,0.4-3.0 mm wide, annual;axillaryor apicaldormant
turions developing. Submergedleaves sessile, linear, 35-80(-135) mm long, 1.8-3.8(-5.5) mm wide,
13-30(-40) timesas long as wide, brightgreento darkgreen,sometimeswitha reddishtinge,3-veined,with
16-24 additionalsclerenchymatous
strands,borderedby a strongmarginalvein, withnarrowrows of lacunae
288
G. Wiegleb & Z. Kaplan
borderingthe midrib,entireat margins,narrowlycuneateat base, acuteto acuminateat apex.Floatingleaves
always absent.Stipulesaxillary,convolute,1O-21(-29) mm long, translucentto opaque,persistentbut soon
erodingto fibrousstrandsat the apex.Peduncles3-15(-26) mm long, 1-6 times as long as the fruitingspike,
as thick as the stem. Spikes almostglobose, 4-8 mm long in fruit,contiguous.Flowers4-7, with 1 carpel.
Fruits3.0-4.0(-4.7) mm long, dorsalkeel distinct.
Stem anatomy
Stele of oblong type, endodermisof 0-type, interlacunarbundles absent, subepidermalbundles present,
multicellular,
pseudohypodermis
absent.
Distribution
Temperateregionsof Europe,W Asia?
Hybrids
41 x 47. P. xpseudofriesii DANDYet G. TAYLOR,
Kew Bull. 12: 332. 1957.
[= P acutifoliusx P.friesii]
41 x 48. P. xsudermanicus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 73. 1916.
[= P acutifoliusx P pusillus]
Notes
(1) P acutifoliusis a species closely relatedto P compressus. Even thoughnot alwayseasily recognizablein
its non-floweringstate,it is distinguishedin manycharactersof its inflorescenceandflower/fruitmorphology.
UnlikeP compressus,it occupiesa limitedgeographicalarea.
(2) P henningiiA. BENN.hasbeenrecentlyreportedfromseveralplacesin Siberia(VOLOBAEV1993).However,
the present-dayconceptis unlikelyto correspondto the originalone. Biosystematicalrevisionof the whole
groupis desirable.
(3) Theoccurrenceof the hybridP acutifoliusx P compressushasrepeatedlybeenclaimedto arise.However,
bothparentsareoftenindistinguishable
vegetativelyowingto significantoverlapof characters.Therefore,their
hybridcannotbe identifiedon the basis of non-floweringspecimens.Experimentalcrossingis necessaryto
confirmthe existenceof the hybrid.
42. Potamogeton compressus Linnaeus, Sp. Pi. 127. 1753. ("compressum")
= P zosterifolius SCHUMACH.,
Enum.P1. 1: 50. 1801. ("zosterefolium")
= P zosterophyllus DUMORT.,Fl. Belg. 164. 1827, nom. illeg.
= Spirilluszosterifolius(SCHUMACH.)
NIEUWL.,Amer.Midl.Naturalist3: 17. 1913.
= P complanatusWILLD.,Ges. Naturf.FreundeBerlinMag. NeuestenEntdeck.GesammtenNaturk.3: 297.
1809. ("complanatum")
= P laticaulisWAHLENB.,Fl. Suec. 1: 107. 1824. ("laticaule')
= P carinatus KUPFFERin MUHLEN,Korrespondensbl. Naturf.-Vereins Riga 49: 164. 1906.
_ P acutifolius subsp. carinatus (KUPFFER)GRAEBN.in ENGL.,Pflanzenr. 31 (IV.11): 104. 1907.
= P monoginus MIKI,Water Phan. Japan 18. 1937.
Description
Rhizome absent or filiform, compressed, annual, usually short. Stem richly branched, filiform to slender,
strongly flattened, 0.5-3.4(-4.8) mm wide, annual; axillary or apical dormant turions developing. Submerged
leaves sessile, linear, (70-)85-240(-290) mm long, (2.2-)2.9-5.4(-6.0) mm wide, 20-60(-90) times as long
as wide, olive green to dark green, sometimes with a reddish tinge, (3-)5-veined, with 20-32 additional
sclerenchymatous strands, bordered by a strong marginal vein, with narrow rows of lacunae bordering the
midrib, entire at margins, narrowly cuneate at base, acute to mucronate at apex. Floating leaves always absent.
Stipules axillary, convolute, (19-)22-35(-55) mm long, translucent to opaque, persistent but eroding early to
fibrous strands at the apex. Peduncles (21-)28-69(-95) mm long, 2-5 times as long as the fruiting spike, as
thick as the stem. Spikes cylindrical, 16-33 mm long in fruit, contiguous. Flowers 10-20, with (1-)2(-3)
carpels. Fruits 3.4-4.0 mm long, dorsal keel distinct.
Stem anatomy
Stele of oblong type, endodermis of 0-type, interlacunar bundles absent, subepidermal bundles present,
multicellular, pseudohypodermis absent.
Taxonomy of Potamogeton
289
Distribution
Borealand temperateregionsof EuropeandAsia.
Hybrids
42 x 46. P. xfauriei (A. BENN.)MIKI,Water Phan. Japan 45. 1937. ("Fauriei")
[= P compressus x P oxyphyllus]
_ P oxyphyllus var.fauriei A. BENN.,J. Bot. 42: 76. 1904. ("Fauriei")
43. Potamogeton
zosteriformis
FERNALD,Mem. Amer. Acad. Arts Sci. 17: 36. 1932.
P. zosterifolius subsp. zosteriformis (FERNALD)HULTEN,Kungl. Svenska Vetenskapsakad. Handl., ser. 4,
8(5) [Circump.P1. 1]: 168. 1964.
= P zosterifolius var.minor HOOK.,Fl. Bor.-Amer.2: 172. 1838.
= P zosterifoliusvar.americanusA. BENN.,Trans.& Proc.Bot. Soc. Edinburgh29(1):46. 1924.
Description
Rhizomeabsentor filiformto slender,compressed,annual.Stemrichlybranched,filiformto slender,flattened,
0.6-3.2 mm wide, annual;axillaryor apicaldormantturionsdeveloping.Submergedleaves sessile, linear,
50-200 mmlong,(1.8-)2.3-5.0 mmwide,25-50 timesas longas wide,brightgreento darkgreen,sometimes
witha reddishtinge,3-veined,with20-34 additionalsclerenchymatous
strands,borderedby a strongmarginal
vein, with narrowrows of lacunaeborderingthe midrib,entireat margins,narrowlycuneateat base, acuteto
mucronateat apex. Floatingleaves always absent.Stipulesaxillary,convolute,(16-)20-32(-40) mm long,
translucent,
persistent,generallyintactthroughout
the season.Peduncles(19-)30-100 mm long, 1.5-5.0 times
as long as the fruitingspike, as thick as the stem. Spikescylindrical,15-32 mm long in fruit,contiguous.
Flowers10-20, with (1-)2 carpels.Fruits4.0-5.0(-5.5) mm long, dorsalkeel distinct.
Stem anatomy
Stele of oblong type, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundlespresent,
pseudohypodermis
absent.
Distribution
NorthAmerica.
Hybrids
51 x 43. P. xhaynesii HELLQ.et G.E. CROW,Brittonia 38(4): 415. 1986.
[= P. strictifolius x P zosteriformis]
53 x 43. P. xogdenii HELLO.
et R.L. HILTON,
Syst. Bot. 8(1): 88. 1983, pro sp.
[= P. hillii x P. zosteriformis]
Notes
(1) P zosteriformisis closely relatedto P compressus.They are vicariantin theirdistribution.The former
occursin NorthAmericawhile the latteris Eurasian.
(2) P ogdeniiwas describedas a speciesof hybridogenous
origin.The speciesnaturewasjustifiedespecially
by the rich fruit production. However, especially P xangustifolius, but also P xfluitans and P xsudermanicus,
arealso knownto producefruits.Nothingis known,however,aboutthe viabilityandgerminationrateof these
fruits.Even thoughP xogdeniiis clearlyintermediate
betweenthe putativeparents,its speciesstatusmay be
substantiated
in futurestudies.
44. Potamogeton
manchuriensis
(A. BENNETT)A. BENNETT,Trans. & Proc. Bot. Soc. Edinburgh
29: 50. 1924. ("mandschuriensis")
P acutifolius subsp.manchuriensis A. BENN.,J. Bot. 42: 76. 1904.
-
P manchuriensis (A. BENN.)FERNALD,Mem. Amer. Acad. Arts Sci. 17: 68. 1932. [isonymum]
Description
Rhizome filiform, slightly compressed,perenniail.Stem sparinglyto richly branched,filiform, slightly
compressed,annual;axillaryor apicaldormanlt
tlrions developing.Submergedleaves sessile, linear,40-150
mm long, 1.5-2.5 mm wide, 25-60 times as long as wide, olive green to darkgreen,3-veined,with 10-18
additionalsclerenchymatous
strands,borderedby a strongmarginalvein,withnarrowrowsof lacunaebordering
the midrib,entireat margins,narrowlycuneateat base, acuminateat apex. Floatingleaves always absent.
290
G. Wiegleb & Z. Kaplan
Stipulesaxillary,convolute, 18-30 mm long, translucentto opaque,persistentbut erodingearly to fibrous
strandsat the apex.Peduncles20-55 mmlong, 2.5-3.5 timesas long as the fruitingspike,as thickas the stem.
Spikescylindrical,6-17 mm long in fruit,contiguous.Flowerandcarpelnumbersunknown.Fruits2.8-3.5
mm long, dorsalkeel distinct.
Stem anatomy
Stele of oblong type, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundles present,
pseudohypodermis
absent.
Distribution
NE Asia.
Note
(1) P manchuriensisis insufficientlyknown.At presentit is regardedas being relatedto P. compressus.
45. Potamogeton sibiricus A. BENNETT,
J. Bot. 28: 300. 1890.
= P subsibiricusHAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 84. 1916.
= P porsildiorusFERNALD,Mem. Amer.Acad. ArtsSci. 17:40. 1932. ("Porsildiorum")
= P anadyrensisV.N. VASSIL.,Bot. Mat. Gerb.Bot. Inst. Akad.Nauk SSSR [= Not. Syst. Herb.Inst.Bot.
Acad. Sci. URSS] 17:45. 1955.
Description
Rhizomefiliform,slightlycompressed,perennial.Stem unbranchedor sparinglybranched,filiform,slightly
compressed,annual;axillaryorapicaldormantturionsdeveloping.Submergedleavessessile,linear,35-80(-95)
mm long, 1.2-2.0(-2.5) mm wide, 20-40 times as long as wide, olive greento darkgreen, 3-veined,with
(8-)12-20 additionalsclerenchymatousstrands,borderedby a strongmarginalvein, with narrowrows of
lacunaeborderingthe midrib,entireat margins,narrowlycuneateat base, acuteto roundedor mucronateat
apex.Floatingleaves alwaysabsent.Stipulesaxillary,convolute,(10-)15-25 mm long, translucentto opaque,
persistentbuterodingearlyto fibrousstrandsat the apex.Peduncles17-35(-50) mm long, 1-3 timesas long
as the fruitingspike,as thick as the stem. Spikescylindrical,7-17 mm long in fruit,contiguous.Flowerand
carpelnumbersunknown.Fruits2.1-3.0 mm long, dorsalkeel distinct.
Stem anatomy
Stele of oblong type, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundlespresent,
pseudohypodermis
absent.
Distribution
NE Europe,N Asia, NW andN NorthAmerica.
Note
(1) P sibiricusis insufficientlyknown.Most probablyit is relatedto P oxyphyllusor P compressus.
46. Potamogeton oxyphyllus MIQUEL,
Ann. Mus. Bot. Lugduno-Batavum 3: 161. 1867.
= ? P chongyangensisW.X.WANG,Acta Phytotax.Sin. 22(6): 490. 1984.
Description
Rhizome filiform, terete, perennial,continouslygrowing. Stem richly branched,filiform, terete, mostly
wintergreen;
axillarydormantturionsdeveloping.Submergedleavessessile,linearto narrowlylinear-lanceolate,
50-105(-135) mm long, 2.0-3.5(-4.2) mm wide, 20-40 times as long as wide, brightgreen to darkgreen,
5-7(-9)-veined, with (2-)8-16(-20) faintadditionalsclerenchymatous
strands,borderedby a strongmarginal
vein, withnarrowrows of lacunaeborderingthemidrib,entireat margins,narrowlycuneateat base,acuminate
at apex. Floatingleaves always absent.Stipulesaxillary,convolute,15-25 mm long, translucent,persistent.
Inflorescenceaxillary.Peduncles20-45 mmlong, 2-3 timesas long as the fruitingspike,as thickas the stem.
Spikescylindrical,6-15 mm long in fruit,contiguous.Flowers5-9, with 4 carpels.Fruits3.2-3.8 mm long,
dorsalkeel indistinct.
Stem anatomy
Stele of oblong type, endodermisof 0-type, interlacunarbundles absent, subepidermalbundles present,
pseudohypodermis
absent.
Taxonomy of Potamogeton
291
Distribution
E andSE Asia.
Hybrids
37 x 46. P. xkyushuensis KADONO
et WIEGLEB,
J. Jap. Bot. 62(3): 76. 1987.
[= P maackianus x P oxyphyllus]
42 x 46. P. xfauriei (A. BENN.)MIKI,Water Phan. Japan 45. 1937. ("Fauriei")
[= P compressus x P. oxyphyllus]
46 x 48. P. xorientalis HAGSTR.,
Bot. Not. 1908: 102. 1908, pro sp.
[= P oxyphyllus x P. pusillus]
- P henryiFERNALD,
Mem. Amer.Acad.ArtsSci. 17: 73. 1932. ("Henryi")
56 x 46. P. xkamogawaensis MIKI,Bot. Mag. (Tokyo) 48: 328. 1934.
[= P. octandrus x P. oxyphyllus]
Note
(1) P xorientalisis a widespreadhybridoccurringalmostthroughout
theareaof P oxyphyllus.Despiteits vital
andabundantgrowthit is completelysterile.
47. Potamogeton
friesii RUPRECHT,Beitr. Pflanzenk. Russ. Reiches 4: 43. 1845. ("Friesii")
P pusillus subsp. friesii (RUPR.)HOOK.f., Stud.Fl. Brit.Isl. ed. 3. 435. 1884. ("Friesii")
Spirillusfriesii(RUPR.)NIEUWL.,
Amer.Midl.Naturalist3: 17. 1913.
-P mucronatusSCHRAD.
ex ROEM.
et SCHULT.,
Syst. Veg.ed. 16. 3: 517. 1818,nom. nud.
= P compressus var. ,B.acutus SCHLTDL.,
Fl. Berol. 1: 117. 1823.
= P compressus [var.] P. elongatus WAHLENB.,Fl. Suec. 1: 107. 1824. ("elongatum")
- P pusillus[var.]("spielart")
a. latifoliusG. MY., ChlorisHan.525. 1836,nom. illeg.
= P pusillus[var.]a. majorFR.,Novit.Fl. Suec.ed. 2. 48. 1828,nom.illeg., nonMERT.
et W.D.J.KOCH1823.
P
=P
=P
-
P major [FR.] MORONG,Mem. Torrey Bot. Club 3(2): 41. 1893. [non vidimus]
mucronatus SCHRAD.ex RCHB.,Icon. Fl. Germ. Helv. 7: 15. t. 24. 1845, pro syn.
oederi G. MEY.,Fl. Hanov. Exscurs. 536. 1849. ("Oederi")
mucronatus SCHRAD.ex SONDER,Fl. Hamburg. 99. 1850. ("1851")
P pusillusvar.mucronatus(SCHRAD.
ex SONDER)
HOOK.
f., Stud.Fl. Brit.Isl. 374. 1870.
P pusillus[subsp.]b) mucronatus(SCHRAD.
ex SONDER)
CELAK.,
Analyt.Kvet.Cech,Mor.a Rak.Slezska
ed. 3. 44. 1897.
-
P compressus var. dimidius CREP.,Notes P1. Rar. Belgique 4: 44. 1864.
Description
Rhizomeabsentor present,filiform,compressed,annual,short.Stem richlybranched,filiform,compressed,
annual;axillaryor apicaldormantturionsdeveloping.Submergedleavessessile,linear,(31-)40-85(-100) mm
long, 1.5-3.5(-4.0) mm wide, 15-45 times as long as wide, brightgreen, sometimeswith a reddishtinge,
(3-)5(-7)-veined, withoutadditionalsclerenchymatous
strands,borderedby a faintmarginalvein, withnarrow
rowsof lacunaeborderingthe midrib,entireat margins,narrowlycuneateat base,mucronateat apex.Floating
leaves alwaysabsent.Stipulesaxillary,shortlyconnateonly at base andsplitintotwo remnantsat apex,7-25
mm long,opaque,whitish,persistent.Peduncles15-40(-70) mmlong, 1-5 timesas long as the fruitingspike,
as thickas the stem. Spikes cylindrical,7-14 mm long in fruit,contiguousto shortlydistant.Flowers4-8,
with 4 carpels.Fruits2.4-3.0 mm long, dorsalkeel indistinct.
Stem anatomy
Stele of circulartype, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundlespresent,
pseudohypodermis
absent.
Distribution
borealandtemperateregionsthroughoutthe northernhemisphere.
Circumpolar,
Hybrids
35 x 47. P. xlintonii FRYER,J. Bot. 38: 366. 1900; FRYER,Bot. Exch. Club Brit. Isles Rep. 1899-1900: 21.
1900. ("Lintoni")
[= P crispus x P friesii]
292
G. Wiegleb & Z. Kaplan
41 x 47. P. xpseudofriesii DANDY et G. TAYLOR, Kew Bull. 12: 332. 1957.
[= P acutifolius x P friesii]
pusillus LINNAEUS,Sp. Pi. 127. 1753.
- P pusillus [subsp.] a) genuinus CELAK.,Analyt. Kvet. Cech, Mor. a Rak. Slezska ed. 3. 43. 1897, nom.
inval.
Spirillus pusillus (L.) NIEUwL.,Amer. Midl. Naturalist 3: 18. 1913.
= P pusillus [var.] a. major MERT.et W.D.J. KOCH,Rohlings Deutschl. Fl. ed. 3. 1: 857. 1823.
= P pusillus var. P. tenuissimus MERT.et W.D.J. KOCH,R6hlings Deutschl. Fl. ed. 3. 1: 857. 1823.
= P pusillus [subsp.] P. tenuissimus (MERT.et W.D.J. KOCH)SCHUBL.et G. MARTENS,Fl. Wurttemb. 112.
1834.
P. tenuissimus (MERT.et W.D.J. KoCH) RCHB.,Icon. Fl. Germ. Helv. 7: 14, t. 22, fig. 39. 1845.
- P pusillus subsp. tenuissimus (MERT.et W.D.J. KOCH)R.R. HAYNESet HELLQ.,Novon 6(4): 370. 1996.
[isonymum]
= ? P. denticulatus LINKin BUCH,Phys. Beschr. Canar. Ins. 138. 1825.
= P. gracilis FR., Novit. Fl. Suec. ed. 2. 50. 1828, nom. illeg., non WOLFG.1827.
P noltei A. BENN.,J. Bot. 28: 300. 1890. ("Noltei")
= P panormitanus BIv. in A. BIv. f., Nuove Piante 6. 1838.
P pusillus var. panormitanus (Biv.) A. BENN.,J. Bot. 19: 242. 1881.
P pusillus subsp. panormitanus (BIv.) G. FISCH.in DORFLER,
Herb. Norm. no. 4767. 1905.
P pusillus proles panonnitanus (BIV.) GRAEBN.in ENGL.,Pflanzenr. 31 (IV.11): 116. 1907.
= P panormitanus var. minor BIv. in A. BIv. f., Nuove Piante 6. 1838.
= P berchtoldii FIEBERin BERCHT.et OPIZ,Oekon.Techn. Fl. Bohm. 2(1): 277. 1838; FIEBERin BERCHT.et
FIEBER,Potam. Bohmens 40. 1838. ("Berchtoldi")
P pusillus subsp. berchtoldii (FIEBER)MAGNIN,Bull. Soc. Bot. France 43: 446. 1896. ("Berchtoldi")
P pusillus var. berchtoldii (FIEBER)ASCH.et GRAEBN.,Synops. Mitteleur. Fl. 1: 345. 1897.
P pusillus proles berchtoldii (FIEBER)GRAEBN.in ENGL.,Pflanzenr. 31 (IV.I 1): 15. 1907. ("Berchtoldii")
= P. berchtoldii [var.] a. mucronatus FIEBERin BERCHT.et OPIZ,Oekon.-Techn. Fl. Bohm. 2(1): 277. 1838;
FIEBERin BERCHT.et FIEBER,Potam. Bohmens 40. 1838.
= P berchtoldii [var.] P. acuminatus FIEBERin BERCHT.et OPIZ,Oekon.-Techn. Fl. Bohm. 2(1): 278. 1838;
FIEBERin BERCHT.et FIEBER,Potam. Bohmens 41. 1838.
= P grisebachii HEUFF.,Verh. K. K. Zool.-Bot. Ges. Wien 8: 200. 1858. ("Grisebachii")
= ? P. berteroanus PHIL.,Linnaea 30: 200. 1859-1860. ("Berteroanus")
= P subtrichoides SCHUR,Enum. P1. Transsilv. 633. 1866.
= P pusillus var. gemmiparus J.W. ROBBINSin A. GRAY,Manual Bot. North. U. S. ed. 5. 489. 1867.
- P gemmiparus J.W. ROBBINSin A. GRAY,Manual Bot. North. U. S. ed. 5. 489. 1867, pro syn.
P gemmiparus (J.W. ROBBINS)MORONG,Bot. Gaz. (Crawfordsville) 5: 51. 1880.
P pusillus subsp. gemmiparus (J.W. ROBBINS)R.R. HAYNESet HELLQ., Novon 6(4): 370. 1996.
= P tenuifolius F PHIL.,Anal. Mus. Nac. Chile 2(8): corr. pag. 95. 1891, nom. illeg., non RAF. 1811.
_ P aschersonii A. BENN.,J. Bot. 31: 294. 1893. ("Aschersonii")
= P trinervius G. FISCH.,Ber. Bayer. Bot. Ges. 11: 29 et 123. 1907, pro hybr. P pusillus (sub P panormitanus)
x P trichoides.
= ? P uruguayensis A. BENN.et GRAEBN.in ENGL.,Pflanzenr. 31 (IV.l 1): 1 11. 1907.
= P pusillus subsp. argentinus A. BENN.,J. Bot. 46: 250. 1908.
= P turionifer HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 91. 1916, pro hybr. P foliosus x
P pusillus.
= ? P pusilliformis HAGSTR.,Kungl. Svenska Vetenskapsakad.Handl. 55(5): 97. 1916, pro hybr. P.friesii (sub
P mucronatus) x P pusillus.
= P dualis HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 103. 1916, pro hybr. P panormitanus x
P pusillus.
= P badius HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 104. 1916.
= ? P antaicus HAGSTR.,Kungl. Svenska Veteniskapsakad.Handl. 55(5): 105. 1916.
= P exiguus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 106. 1916.
= P lacunatus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 120, fig. 53. 1916.
48. Potamogeton
Taxonomy of Potamogeton
= ? P loculosus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 120. 1916.
= ? P. groenlandicus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 127. 1916.
_ ? P pusillus subsp. groenlandicus (HAGSTR.)BOCHER,Meddel. Groenland 147(9): 44.
293
1952.
= P subjavanicus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 129. 1916.
= P pusillus subsp. lacustris PEARSALL et PEARSALLf., J. Bot. 59: 163. 1921.
_ P lacustris (PEARSALL et PEARSALL f.) DRUCE,List Brit. P1. ed. 2. 117. 1928.
= ? P tubulatus HAGSTR.in HEDIN,Southern Tibet 6(3): 96. 1922.
= P clystocarpus FERNALD,Mem. Amer. Acad. Arts Sci. 17: 79. 1932.
= P hoggarensis DANDY,J. Linn. Soc., Bot. 50: 522. 1937.
= P millardii HESL.HARR., Proc. Univ. Durham Phil. Soc. 10: 365. 1942.
= P skvortsovii KLINKOVA,
Byull. Glavn. Bot. Sada 1993(168): 48. 1993.
Description
Rhizome absent or present later in the growing season, filiform, terete, annual to biennial. Stem sparingly to
richly branched, filiform, terete to slightly compressed, annual to perennial; axillary or apical dormant turions
developing, rarely directly on rhizomes, or sometimes not developing. Submerged leaves sessile, linear,
(15-)20-85(-110) mm long, (0.3-)0.8-2.5(-3.1) mm wide, (15-)20-60(-90) times as long as wide, bright
green to olive green or dark green, sometimes with a brownish tinge, (1-)3(-5)-veined, without additional
sclerenchymatous strands, mostly bordered by a faint marginal vein, with or without narrow or sometimes
broad rows of lacunae bordering the midrib, entire at margins, narrowly cuneate at base, acuminate or acute
to subobtuse at apex. True floating leaves absent but rarely the uppermost leaves with lamina floating at the
water surface, subsessile, linear-oblanceolate, 18-38 mm long, 1.3-3.5 mm wide, 7-20 times as long as wide,
translucent, membranous to almost subcoriaceous, bright green, 3-5-veined, with broad rows of lacunae
bordering the midrib, narrowly cuneate at base, acute to narrowly obtuse at apex. Stipules axillary, convolute
or connate, 4-18(-32) mm long, translucent, persistent to decaying. Peduncles (6-)10-45(-80) mm long, 1-6
times as long as the fruiting spike, as thick as the stem. Spikes cylindrical, 4-13 mm long in fruit, contiguous
to shortly distant. Flowers 2-7, with (3-)4(-7) carpels. Fruits 1.8-2.7(-3.3) mm long, dorsal keel indistinct.
Stem anatomy
Stele of circular type, rarely of oblong type, endodermis of 0-type, interlacunarbundles absent, subepidermal
bundles present, pseudohypodermis absent or partly 1-layered.
Distribution
Europe, Africa, Asia, North America and South America.
Hybrids
1 x 48. P. xrivularis GILLOT
in MAGNIER,
Scrin. Fl. Select. 6: 118. 1887.
[= P polygonifolius x P pusillus]
3 x 48. P. xianceolatus SM. in SOWERBY,
ENGL.Bot. 28: t. 1985. 1809, pro sp. ("lanceolatum")
[= P coloratus x P pusillus]
25 x 48. P. xvariifolius THORE,Essai Chloris 47. 1803, pro sp. ("variifolius")
[= P natans x P pusillus]
26 x 48. P. xmysticus MORONG,
Bot. Gaz. (Crawfordsville) 5: 50. 1880, pro sp.
[= P. perfoliatus x P pusillus]
38 x 48. P. xattenuatus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 112. 1916.
[= P. polygonus x P pusillus]
41 x 48. P. xsudermanicus HAGSTR.,Kungi. Svenska Vetenskapsakad. Handl. 55(5): 73. 1916.
[= P acutifolius x P. pusillus]
46 x 48. P. xorientalis HAGSTR.,
Bot. Not. 1908: 102. 1908, pro sp.
[= P. oxyphyllus x P pusillus]
48 x 55. P. xgrovesii DANDY
et G. TAYLOR,
Watsonia6: 316. 1967.
[= P. pusillus x P. trichoides]
56 x 48. P. xapertus MIKI,Bot. Mag. (Tokyo) 49: 690. 1935.
[= P octandrus x P pusillus]
294
G. Wiegleb & Z. Kaplan
Notes
(1) P.pusillusis regardedhereas a highlypolymorphicspecieswithnumerousregionalformsandecomorphoses.
Moredetailedclassificationseems to be impossiblebecauseof the highlyreticularvariation.No correlatedset
of characterswhich wouldmakediscrimination
of taxapossiblehavebeen confirmed.
(2) The SouthAmericanP. pusillushas been oftentreatedas a separatespecies,viz P. berteroanus.However,
these plantsfall well withinthe variationpatternof P. pusillusas definedhere.
(3) ManyauthorsregardP. berchtoldiiand/orP gemmiparusas a separatespecies of the respectiveregions
wherethey occur.TheirdistinctionfromP. pusilluss. str.is, however,insufficient.
(4) Some of the plantscalled P. groenlandicusshow certaincharactersdeviantfromthe presentconceptof P
pusillus.They are characterizedespeciallyby the leaves with up to 8 additionalsclerenchymatous
strands.
Theseplantsareknownonly froma geographicallylimitedareain WesternGreenland.Furtherresearch,such
as experimentalcultivation,is necessaryin orderto clarifytheirstatus.
(5) P clystocarpus and P hoggarensis are regarded as extreme local morphotypes of P pusillus. Both are
knownonly fromthe type locality.
(6) ManyhybridsbetweenspecieswithintheP pusillus-grouphavebeenproposed.Linear-leavedspecieshave
a reducedmorphologicalvariationandarephenotypically
extremelyvariableandplastic.Distinguishinghybrids
on a solely morphologicalbasis is generallyavoided.Consequentlymanyproposednamesof allegedhybrids
cannotbe acceptedon the basisof ourpresentstateof knowledge.Crossingexperimentsarenecessaryto solve
this problem.
49. Potamogeton gayiA. BENNETT,
Ann. K. K. Naturhist. Hofmus. Wien 7(4): 293. 1892. ("Gayii")
= P burkartiiHORNex TURin CABRERAet al., Fl. Prov.BuenosAires 4(1): 287. 1968.
Description
Rhizomefiliformto slender,terete,perennial,long, regularlyproduced.Stem sparinglyto richlybranched,
filiform,tereteto slightlycompressed,perennial;axillarydormantturionssometimesdeveloping.Submerged
leaves sessile, linear,55-100 mm long, (2-)3-6 mm wide, 18-25 timesas long as wide, brightgreento dark
green,oftenwitha reddishorbrownishtinge,3-5-veined,withoutadditionalsclerenchymatous
strands,bordered
by a strongmarginalvein, with narrowrows of lacunaeborderingthe midrib,entireat margins,narrowly
cuneateat base, acute at apex. Floatingleaves always absent.Stipulesaxillary,convolute,14-20 mm long,
translucent,persistentto decaying.Peduncles15-60 mm long, 1.5-4.5 times as long as the fruitingspike,as
thickas the stem.Spikescylindrical,10-17 mm long in fruit,contiguous.Flowers5-12, with4 carpels.Fruits
4.3-4.6 mm long, dorsalkeel distinct.
Stem anatomy
Steleof oblongtype,endodermisof 0 type,interlacunar
bundlesabsentor rarelypresent,subepidermal
bundles
present,multicellular,pseudohypodermis
1(-2)-layered.
Distribution
SouthAmerica.
Note
(1) P gayi is closely relatedto P.pusillus.However,it deviatesfromthe variationpatternof the latterspecies
and it is confinedto a restrictedgeographicalarea.
50. Potamogeton rutilus WOLFGANG
in SCHULTES
et SCHULTES
f., Mant. 3: 362. 1827.
P pusillusvar.rutilus(WOLFG.)WIEDEM.et E. WEBER,Beschr.Phan.Gew.Esth-,Liv-Curl.94. 1852.
- P cespitosusNOLTEex RCHB.,Icon. Fl. Germ.Helv.7: 15, t. 23, fig. 41. 1845, pro syn. ("cespitosum")
Description
Rhizomeabsentor filiform, slightly compressed,annual.Stem unbranchedor sparinglybranched,filiform,
slightlycompressed,annual;axillarydormantturionsdeveloping.Submergedleavessessile, linear,32-75 mm
long,0.5-1.1 mmwide, 35-80 timesas long as wide,brightgreen,sometimeswitha brownishtinge,somewhat
rigid,3-veined,withoutadditionalsclerenchymatous
strands,borderedby a strongmarginalvein,withoutrows
of lacunaeborderingthe midrib,entireat margins,narrowlycuneateat base,acuminateat apex.Floatingleaves
alwaysabsent.Stipulesaxillary,shortlyconnate,15-20 mmlong,opaque,fibrous,whitish,persistent.Peduncles
(3-)10-17 mmlong, 1-3 timesas long as the fruitingspike,as thickas the stem.Spikescylindrical,4-10 mm
long in fruit,contiguous.Flowers5-6, with (2-)4 carpels.Fruits2.0-2.1 mm long, dorsalkeel indistinct.
Taxonomy of Potamogeton
295
Stem anatomy
Stele of circulartype, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundlespresent,
pseudohypodermis
absent.
Distribution
W, N andC Europe,W Asia.
Note
(1) P rutilusis relatedto P. pusillus. It comprisesplants with a special set of charactersof a restricted
geographicalarea.
51. Potamogeton strictifolius A. BENNETT,
J. Bot. 40: 148. 1902.
P pusillusvar.pseudorutilusA. BENN.,J. Bot. 39: 201. 1901. ("pseudo-rutilus")
- P strictifolius var. typicus FERNALD,
Mem. Amer. Acad. Arts Sci. 17: 56. 1932, nom. inval.
= P strictifolius var. rutiloides FERNALD,Mem. Amer. Acad. Arts Sci. 17: 57. 1932.
= P pusillusvar.rutiloides(FERNALD)
B. BOIVIN,
NaturalisteCanad.94: 527. 1967.
= P longiligulatus FERNALD,Mem. Amer. Acad. Arts Sci. 17: 66. 1932.
Description
Rhizomefiliform,terete,annual,short.Stem unbranchedor branched,filiform,slightlycompressed,annual;
axillaryor apicaldormantturionsdeveloping.Submergedleaves sessile, linear,12-63 mm long, 0.6-2.0 mm
wide, 20-40 times as long as wide, bright green, sometimes with a brownishtinge, somewhatrigid,
3-5(-7)-veined, withoutadditionalsclerenchymatous
strands,borderedby a strongmarginalvein, without
rows of lacunaeborderingthe midrib,entireat margins,narrowlycuneateat base,acuteto acuminateat apex.
Floatingleaves alwaysabsent.Stipulesaxillary,connate,6-16 mm long, opaque,fibrous,whitish,persistent.
Peduncles10-45 mm long, 1.5-3.5 timesas long as the fruitingspike,as thickas the stem,slightlythickened
upwards.Spikescylindrical,6-13 mm long in fruit,contiguous.Flowers5-7, with 4 carpels.Fruits1.9-2.1
mm long, dorsalkeel indistinct.
Stem anatomy
Stele of circulartype, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundlespresent,
pseudohypodermis
absent.
Distribution
NW,C and E NorthAmerica.
Hybrids
51 x 43. P. xhaynesii HELLQ.et G. E. CROW,
Brittonia38(4):415. 1986.
[= P strictifoliusx P zosteriformis]
Note
(1) P strictifoliusis closely relatedto P rutilus.It is distinguishedmainlyon quantitativecharacters.
52. Potamogeton foliosus RAFINESQUE,
Med. Repos., Hexade 3, 2: 409. 1811. ("foliorum")
- P foliosus RAF.,Med. Repos.,Hexade2, 5: 354. 1808, nom. prov.("foliosum")
= P pauciflorusPURSH,Fl. Amer.Sept. 1: 121. 1814,nom. illeg. ("pauciflorum")
= Spirillusfoliosus (RAF.) NIEUWL.,Amer. Midl. Naturalist 3: 18. 1913.
P foliosus var.genuinusFERNALD,Mem.Amer.Acad.ArtsSci. 17: 43. 1932, nom. inval.
= P niagarensisTUCK.,Amer.J. Sci. Arts,ser.2, 7: 354. 1849.
= P pauciflorusvar.niagarensis(TUCK.)J.W. ROBBINSin A. GRAY,ManualBot. North.U. S. ed. 2. 435.
1856.
= P foliosus var.niagarensis(TUCK.)MORONG,Mem.TorreyBot. Club3(2): 39. 1893.
-
= Spirillusfoliosusvar.niagarensis(TUCK.)
NIEUWL.,
Amer.Midl.Naturalist3: 18. 1913.
= P pauciflorusvar.californicusMORONG,
Bot. Gaz. (Crawfordsville)10: 254. 1885.
= P foliosus var.californicus(MORONG)
MORONG.
Mem.TorreyBot. Club3(2): 40. 1893.
= P californicus(MORONG)
PIPER,
CoItr. Uitjl. St. N;at.Herb.IlI:98. 1906.
= P curtisiiMORONG,Bull. TorreyBot. Clutb 13: 145. 1886.("Curtsii")
= P.foliosus var. macellusFERNALD, Mein.Amer.Acad.ArtsSci. 17: 46. 1932.
= P fibrillosusFERNALD,
Mem. Amer.Acad.ArtsSci. 17:51. 1932.
296
G. Wiegleb & Z. Kaplan
P foliosus var.fibrillosus(FERNALD)R.R. HAYNESet REVEAL,Rhodora75: 76. 1973.
P foliosus subsp.fibrillosus(FERNALD)R.R. HAYNESet HELLQ.,Novon 6(4): 370. 1996.
Description
Rhizomefiliform,slightlycompressed,perennial.Stembranched,filiform,slightlycompressed,annual;axillary
or apicaldormantturionsdeveloping.Submergedleaves sessile, linear,13-82 mm long, 0.3-2.3 mm wide,
30-60 times as long as wide, brightgreento olive green,sometimeswith a reddishtinge, (1-)3(-5)-veined,
withoutadditionalsclerenchymatous
strands,borderedby a faintmarginalvein, with or withoutnarrowrows
of lacunaeborderingthe midrib,entire at margins,narrowlycuneateat base, narrowlyobtuse or acute to
acuminateat apex. Floatingleaves always absent.Stipulesaxillary,convoluteor connate,2-22 mm long,
translucentto opaque,persistentto decaying.Peduncles3-1 1(-37) mm long, 2-7 timesas long as the fruiting
spike, as thickas the stem, slightlythickenedupwards.Spikesglobose to cylindrical,2-7 mm long in fruit,
contiguous.Flowers2-4, with4 carpels.Fruits1.4-2.7 mm long, dorsalkeel distinct,undulate,dentate,to 0.4
mm high.
Stem anatomy
Stele of circulartype, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundlespresent,
pseudohypodermis
absent.
Distribution
NorthandCentralAmerica.
Note
(1) P foliosus is relatedto P pusillus.It is distinguishedmainlyon the basisof inflorescence,flowerandfruit
characters.
53. Potamogeton hiliii MORONG,
Bot. Gaz. (Crawfordsville) 6: 290. 1881. ("HiIIii")
= P porteri FERNALD,Mem. Amer.Acad.ArtsSci. 17: 73. 1932.("Porteri")
Description
Rhizome absent or present, filiform, slightly compressed,perennial.Stem branched,filiform, slightly
compressed,annual;apical dormantturionsdeveloping.Submergedleaves sessile, linear,20-60 mm long,
0.6-2.5(-4.0) mm wide, 20-40 timesas long as wide,brightgreento olive green,3-veined,withoutadditional
sclerenchymatous
strands,borderedby a faintmarginalvein,withnarrowrowsof lacunaeborderingthemidrib,
entireat margins,narrowlycuneateat base,acuminateat apex.Floatingleavesalwaysabsent.Stipulesaxillary,
convolute,7-16 mm long, translucent,persistent.Peduncles6-14 mm long, 1.5-3.0 times as long as the
fruitingspike, as thick as the stem. Spikes globose, 2-7 mm long in fruit,contiguous.Flowers2-4, with 4
carpels.Fruits2.3-4.0 mm long, dorsalkeel distinct,dentate,to 0.2 mm high.
Stem anatomy
Stele of circulartype, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundlespresent,
pseudohypodermis
absent.
Distribution
E NorthAmerica.
Hybrids
53 x 43. P. xogdenii HELLQ.et R. L. HILTON,
Syst. Bot. 8(1): 88. 1983, pro sp.
[= P. hillii x P zosteriformis]
Note
(1) P hillii is closely relatedto P pusillus.Similarto P foliosus, it is recognizableby some constantcharacters
in a restrictedarea.
54. Potamogeton obtusifolius MERTENS
et W.D.J. KoCH,Rohlings Deutschl. Fl. ed. 3. 1: 855.
1823.
= Spirillusobtusifolius(MERT.et W.D.J. KOCH)NIEUWL.,Amer.Midl. Naturalist3: 19. 1913.
= P compressusvar.,B.tenuis WAHLENB.,Fl. Upsal.60. 1820.
= P compressusvar.et. obtususSCHLTDL.,
Fl. Berol. 1:117. 1823.
= P tataricus LESSING,Linnaea 9: 206. 1834.
Taxonomy of Potamogeton
297
= P obtusifolius[var.]a. angustifoliusFIEBER in BERCHT.
Fl. Bohm.2(1): 275. 1838;
et OPIZ,Oekon.-Techn.
FIEBER in BERCHT.
et FIEBER,Potam.Bohmens38. 1838.
= P. obtusifolius[var.]P. latifoliusFIEBER
in BERCHT.
et OPIZ,Oekon.-Techn.Fl. Bohm. 2(1): 275. 1838;
FIEBER in BERCHT.
et FIEBER,Potam. Bohmens 38. 1838.
= P foliosus var.diffususA. BENN.,Bot. Soc. Exch. ClubBrit.Isles 6: 860. 1923.
Description
Rhizomeabsentor present,filiform,slightlycompressed,annual,oftenshortandnot muchdifferentiated
from
the stem. Stem richly branched,filiform, slightly compressed,annual;apical or axillarydormantturions
developing.Submergedleavessessile,linear,(30-)48-85(-100) mmlong,(1.8-)2.5-3.5 mmwide, 15-30(-38)
times as long as wide, brightgreento darkgreen,often with a reddishtinge,3(-5)-veined,withoutadditional
sclerenchymatous
strands,not borderedby a marginalvein, with narrowto broadrows of lacunaebordering
the midrib,entireat margins,narrowlycuneateat base,obtuseto roundedat apex,oftenveryshortlyandrather
obscurely mucronate.Floating leaves always absent. Stipules axillary,convolute, (6-)10-30 mm long,
translucentto opaque,persistent.Peduncles(5-)8-20(-42) mm long, 1-4 times as long as the fruitingspike,
as thickas thestem.Spikesshortlycylindrical,7-13 mmlongin fruit,contiguous.Flowers6-8, with(3-)4(-5)
carpels.Fruits2.6-3.6 mm long, dorsalkeel indistinctto distinct.
Stem anatomy
Steleof oblongtype,endodermisof 0-type, interlacunar
bundlesabsentora few present,subepidermal
bundles
present,pseudohypodermis
present,1-layered.
Distribution
Circumpolar,
Europe,W andN Asia, N NorthAmerica.
Note
(1) P obtusifoliusis the most distinctspecies of the P pusillus-group,being easy to identifyin most of its
phenotypes.
55. Potamogeton trichoides CHAMISSO
et SCHLECHTENDAL,
Linnaea 2(2): 175, t. 4, fig. 6. 1827.
-P pusillus var. 6. trichoides (CHAM.et SCHLTDL.)
KUNTH,Enum.P1.3: 137. 1841.
= P pusillusvar.,B.capillarisGAUDIN,
FH.Helv. 1: 479. 1828.
= P condylocarpus TAUSCH,Flora19(2): 423. 1836.
= P trichoidesvar.condylocarpus(TAUSCH)
ASCH.et GRAEBN.,
Synops.Mitteleur.Fl. 1: 347. 1897.
= P monogynusJ. GAYin Coss. et GERM.,Suppl.Cat.P1.Env.Paris89. 1843.
= P trichoides var.y. monogynus (J. GAY)MAGNIN,Bull. Soc. Bot. France43: 447. 1896.
= P tuberculatus TEN. et Guss., Syll. P1.Fl. Neapol.,Append.5: 4. 1842.
P trichoidesvar.tuberculatus(TEN. et Guss.) ASCH.,Fl. Brandenb.1: 665. 1864,nom. illeg., non RCHB.
1845.
= P trichoides var. P. tuberculosus RCHB.,Icon. Fl. Germ. Helv. 7: 13, t. 22, fig. 35. 1845.
= P trichoides var.liocarpus ASCH.,Fl. Brandenb.1: 665. 1864.
= P trichoidesvar.trimmeriCASP.,J. Linn.Soc., Bot. 8: 273. 1865. ("Trimmeri")
= P baenitziiGAND.,Oesterr.Bot. Z. 31: 19. 1881. ("Baenitzii")
= P danicus GAND.,Oesterr.Bot. Z. 31: 18. 1881.
= P orthorrhynchus GAND.,Oesterr.Bot. Z. 31: 18. 1881.
= P perneglectus GAND.,Oesterr.Bot. Z. 31: 18. 1881.
= P phialaePOST,Bull. Herb.Boissier 1(8):409. 1893.("Phialae")
= P trichoidesvar.y. phialae (POST)GRAEBN.
in ENGL.,Pflanzenr.31 (IV.11): 120. 1907. ("Phialae")
Description
Rhizomeabsentor presentat the end of the growingseason,filiform,terete.Stemsparinglyto richlybranched,
filiform,terete to slightly compressed,annualto perennial;apical or axillarydormantturionsdeveloping.
Submergedleaves sessile, linear,14-80(-130) mm long, 0.3-1.0(-1.8) mm wide, (30-)40-80(-l 10) timesas
long as wide, brightgreento darkgreen,often with a brownishtinge, 3-veined,lateralveins inconspicuous,
withoutadditionalsclerenchymatous
strands,notborderedby a marginalvein,withoutrowsof lacunaebordering
the midrib,entireat margins,narrowlycuneateat base, acuminateat apex. Floatingleaves always absent.
Stipulesaxillary,convolute,5-27 mm long, translucent,often with a greenishtinge, persistent.Peduncles
10-75 mm long, (2-)3-9 times as long as the fruitingspike,as thickas the stem. Spikes shortlycylindrical,
298
G. Wiegleb & Z. Kaplan
3-9 mm long in fruit,contiguousto shortlydistant.Flowers3-5, with 1(-2) carpels.Fruits2.5-3.2 mmlong,
dorsalkeel distinct.
Stem anatomy
Stele of circulartype, endodermisof 0-type, interlacunarbundlesabsent, subepidermalbundlespresent,
pseudohypodermis
absent.
Distribution
W, C, S andE Europe,N, E andS Africa,W, SW,N andC Asia.
Hybrids
35 x 55. P. xbennetti FRYER,J. Bot. 33: 1, t. 348. 1895. ("Bennettii")
[= P. crispusx P trichoides]
48 x 55. P. xgrovesii DANDYet G. TAYLOR,
Watsonia 6: 316. 1967.
[= P pusillusx P. trichoides]
Note
(1) P trichoidesis closely relatedto P pusillus.It is sometimesdifficultto distinguishfrommorphotypesof
P pusilluswithextremelynarrowleavesin thevegetativestate.Thespeciespossessesa set of uniquecharacters
in flowersandfruit,which alwaysmakeidentificationpossible.
56. Potamogeton octandrus POIRETin LAMARCK,
Encycl. Meth. Bot., Suppl. 4: 534. 1816.
("octandrum")
HydrogetonheterophyllusLOUR., Fl. Cochinch. 1: 244. 1790. ("heterophyllum")
[non Potamogeton
heterophyllus SCHREB.1771]
= P javanicusHASSKARL,Acta Soc. RegiaeSci. Indo-Neerl.1(8):26. 1856.
= P tenuicaulisF. MUELL.,
Fragm.Phyt.Austral.1: 90 et 244. 1858.
= P parvifoliusBUCHENAU,Abh. Naturwiss.VereineBremen7: 32. 1882. ("parvifolia")
= P miduhikimo
MAKINO,
Illustr.Fl. Japan1(9):2, tab. 54. 1891.
= P octandrusvar.miduhikimo(MAKINO)
HARA,J. Jap.Bot. 20: 331. 1944.
- P huillensisWELW.ex SCHINZ,
Ber.Schweiz.Bot. Ges. 1: 61. 1891,pro syn. ("Huillensis")
P limosellifoliusMAXIM.ex KORSH.,TrudyImp. S.-Peterburgsk.
Bot. Sada [= Acta HortiPetrop.]12(2):
393. 1893.
P. octandrus var.limosellifolius (MAXIM.et KORSH.)TZVELEV
in KHARKEV.,
Sosud.Rast.Sovet.Dal'nego
Vostoka2: 323. 1987.
= P asiaticusA. BENN., AnnuaireConserv.Jard.Bot. Geneve9: 103. 1905.
P. octandrusvar.asiaticus(A. BENN.)TZVELEVin KHARKEV.,Sosud.Rast.Sovet. Dal'negoVostoka2:
323. 1987.
= P numasakianus
A. BENN.,AnnuaireConserv.Jard.Bot. Gen&ve9: 104. 1905.
= P javanicus var. b. major A. BENN.ex GRAEBN. in ENGL.,Pflanzenr. 31 (IV. 1): 161. 1907.
- P quinquenervius
HAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 130. 1916.
- P ligulatusHAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 131. 1916.
P subfuscusA. BENN.,J. Bot. 65: 114. 1927.
- P hubeiensisW.X.WANG,
X.Z. SUNet H.Q.WANG,Acta Phytotax.Sin. 26(2): 160. 1988.
= P octandrussubsp.ethiopicusLYE,Lidia3(3): 79. 1993.
Description
Rhizomeabsentor present,filiform,terete,annualor perennial.Stem sparinglyto richlybranched,filiform,
terete,annual;axillarydormantturionsdeveloping.Submergedleaves sessile, linear,25-55(-79) mm long,
0.5-1.2(-1.9) mm wide, 30-75 times as long as wide, brightgreento brown-green,3-veined,lateralveins
inconspicuous,with very broadrowsof lacunaeborderingthe midrib,entireat margins,straightat base,acute
to acuminateat apex.Intermediate
leavesoftenpresent,petiolate,oblongto lanceolate.Floatingleavespresent
or absent,petiolate;laminalinear-oblongto elliptical,sometimeswith parallelmargins,(5-)9-29(-38) mm
long, 3-11 mm wide, 1.3-5.8(-8.5) times as long as wide, opaque,coriaceousto subcoriaceous,brightgreen
to darkgreen,sometimeswitha brownishtinge,5-7-veined,cuneateat base,acuteat apex;petiole3-25(-34)
mmlong,0.2-1.1 timesas longas the lamina.Stipulesaxillary,convolute,4-13 mmlong,translucent,
decaying
early.Inflorescenceterminalor lateral,in theaxilsof floatingandsubmergedleaves.Peduncles9-21 mmlong,
Taxonomy of Potamogeton
299
0.7-2.4 times as long as the fruiting spike, as thick as or slightly thicker than the stem. Spikes cylindrical,
5-16 mm long in fruit, contiguous to shortly distant. Flowers 7-9, with 4(-5) carpels. Fruits 1.5-2.4 mm long,
dorsal keel indistinct to distinct, beak short.
Stem anatomy
Stele of oblong or circular type, endodermis of 0-type, interlacunar bundles absent, rarely a few present,
subepidermal bundles present, pseudohypodermis absent or present, 1-layered.
Distribution
C and S Africa, S and E Asia, Australia.
Hybrids
25 x 56. P. xyamagataensis KADONOet WIEGLEB,J. Jap. Bot. 62(3): 73. 1987.
[= P. natans x P octandrus]
56 x 46. P. xkamogawaensis MIKI,Bot. Mag. (Tokyo) 48: 328. 1934.
[= P octandrus x P. oxyphyllus]
56 x 48. P. xapertus MIKI,Bot. Mag. (Tokyo) 49: 690.1935.
[= P octandrus x P pusillus]
Note
(1) P. octandrus is a highly polymorphic species with reticulate variation.
57. Potamogeton cristatus REGEL
et MAACK
in REGEL,Mem. Acad. Imp. Sci. Saint Petersbourg,
ser. 7, Sci. Phys.-Math., 4(4): 139, tab. 10, fig. 3-6. 1861.
= P iriomotensis MASAMUNE, Trans. Nat. Hist. Soc. Taiwan 24: 281. 1934.
Description
Rhizome absent or filiform, filiform, terete, annual or perennial, short, with vegetative and generative stems.
Stem unbranched or sparingly branched, filiform, terete, annual; axillary dormant turions developing. Submerged
leaves sessile, linear, 30-60 mm long, 0.5-1.0 mm wide, 40-80 times as long as wide, bright green to dark
green, 3-veined, lateral veins inconspicuous, with broad rows of lacunae along the midrib, entire at margins,
straight at base, acute to acuminate at apex. Intermediate leaves often present, petiolate, lanceolate. Floating
leaves present or absent, petiolate; lamina broadly lanceolate to oblong or elliptical, 15-27 mm long, 3-11
mm wide, 2.1-5.0 times as long as wide, opaque, subcoriaceous, bright green to dark green, 7-veined, cuneate
at base, acute to obtuse at apex; petiole 6-14 mm, 0.2-0.7 times as long as the lamina. Stipules axillary,
convolute, 6-10 mm long, translucent, decaying early. Inflorescences mostly lateral, some sometimes terminal,
in the axils of floating leaves. Peduncles 10-20 mm long, 0.8-2.0 times as long as the fruiting spike, as thick
as the stem, slightly thickened upwards. Spikes 10-15 mm long in fruit, contiguous. Flowers 9-11, with (3-)4
carpels. Fruits 1.5-2.5 mm long, dorsal keel distinct, strongly crested with hooked appendages, beak long and
slender.
Stem anatomy
Stele of circular type, endodermis
absent.
of 0-type,
interlacunar bundles
absent, subepidermal
bundles
absent,
pseudohypodermis
Distribution
East Asia (Japan, Korea, China?, Taiwan).
Note
(1) P. cristatus is closely related to P octandrus. It is regarded as a distinct species because it shows a number
of distinct features in a well defined area.
58. Potamogeton vaseyi J.W. ROBBINSin A. GRAY,Manual Bot. North. U. S. ed. 5. 485. 1867.
("Vaseyi")
= P. lateralis MORONG, Bot. Gaz. (Crawfordsville) 5: 51. 1880, p. p.
= P vaseyi var. latifolius MORONG, Mem. Torrey Bot. Club 3(2): 44. 1893.
Description
Rhizome absent or present, filiform, terete, annual or perennial. Stem sparingly to richly branched, filiform,
terete, annual; apical or axillary dormant turions developing, in particular on non-flowering shoots. Submerged
300
G. Wiegleb & Z. Kaplan
leaves sessile, linear,25-80 mm long, 0.1-0.5 mnmwide, 150-250 times as long as wide, brightgreen to
brown-green,3-veined,lateralveins inconspicuous,with narrowrows of lacunaeborderingthe midrib,entire
at margins,straightat base, acuminateat apex. Intermediate
leaves often present.Floatingleaves presentor
absent,petiolate;laminalinear-oblongto ellipticalor obovate,6-15 mm long, 3-8 mm wide, 1.6-2.3 times
as long as wide, opaque,coriaceousto subcoriaceous,brightgreento darkgreen,sometimeswith a brownish
tinge,5-9-veined, cuneateat base, obtuseat apex;petiole3-25 mm long,0.7-2.0 timesas long as the lamina.
Inflorescenceterminalor lateral,in the axils of floatingleaves. Stipulesaxillary,convolute,4-12 mm long,
translucent,decayingearly.Peduncles8-16 mm long, 1.0-2.3 times as long as the fruitingspike,as thickas
or thickerthanthe stem. Spikes cylindrical,6-8 mm long in fruit,contiguousto shortlydistant.Flowers6,
with 4 carpels.Fruits1.6-2.2 mm long, dorsalkeel distinct,beak short.
Stem anatomy
Stele of one bundletype, endodermisof 0-type, interlacunar
bundlesabsent,subepidermalbundlespresent,
pseudohypodermis
absent.
Distribution
E NorthAmerica.
Note
(1) P vaseyiis very similarto P. octandrus.Thereis, however,a largedistributional
gap betweenthe two taxa.
59. Potamogeton confervoides REICHENBACH,
Icon. Fl. Germ. HeIv. 7: 13. 1845.
- P tuckermanii
J.W.ROBBINSin A. GRAY,ManualBot. North.U. S. ed. 2. 434. 1856. ("Tuckermani")
- P monticolusSCHWEIN.
ex A. BENN.,Ann.K. K.Naturhist.Hofmus.Wien7: 292. 1892,prosyn.("monticola")
Description
Rhizomefiliformto slender,terete,perennial,long creeping,with apicalfusiformturions.Stem sparinglyto
richly branched,filiform, terete, annual;apical or axillarydormantturionsdeveloping.Submergedleaves
sessile, filiform,(12-)18-65 mm long, 0.1-0.5 mm wide, 50-150 timesas long as wide, brightgreento dark
green,sometimeswith a reddishtinge, 1-veined,withoutadditionalsclerenchymatous
strands,borderedby a
faintmarginalvein, with narrowrows of lacunaeborderingthe midrib,entireat margins,narrowlycuneateat
base, long acuminateat apex. Floatingleaves always absent.Stipulesaxillary,convolute,5-12 mm long,
translucent,decayingearly.Inflorescence1, rarely2, terminalon primarystem, or rarelyon lower renewal
shoots. Peduncles15-240 mm long, 3-25 times as long as the fruitingspike, as thick as the stem. Spikes
subgloboseto cylindrical,3-12 mm long in fruit,contiguous.Flowers3-5, with4 carpels.Fruits2.2-3.0 mm
long, dorsalkeel distinct.
Stem anatomy
Stele of oblongtype, endodermisof 0-type with strongcell walls, interlacunar
bundlesabsent,subepidermal
bundlesrarelya few present,pseudohypodermis
present,1-2-layered.
Distribution
E NorthAmerica.
Note
(1) P confervoidesis an isolatedspecies withinthe subgenusPotamogeton.
60. Potamogeton spirillus TUCKERMAN,
Amer. J. Sci. Arts, Ser. 2, 6: 228. 1848.
Zannichelliapalustrisvar.gyrocarpaTRIMEN,J. Bot. 12: 370. 1874.
- Spirillustuckermannii
J. GAYex A. BENN.,J. Bot. 28: 298. 1890,pro syn. ("Tuckermanni")
- ZannichelliacochlospermaA. BRAUNex A. BENN.,J. Bot. 28: 298. 1890, pro syn. ("Cochlospermum")
Description
Rhizome slender,compressed,perennial,with overwinteringleafy short shoots. Stem sparinglyto richly
branched,filiformto slender,compressed,annual;specializeddormantturionsnot developing.Submerged
leavessessile, linear,8-80 mmlong,0.5-2.0 mmwide, 15-80 timesas long as wide,brightgreen,1-3-veined,
withoutadditionalsclerenchymatous
strands,not borderedby a marginalvein, usuallywith narrowrows of
lacunaeborderingthe midrib,entire at margins,straightat base, obtuse to acute at apex. Stipulesof the
submergedleaves adnate,convolute, 2-12 mm long, fused with the leaves for 1.5-6.0 mm, translucent,
persistent.Intermediateleaves often present.Floatingleaves shortlypetiolate;laminaoblong to elliptic or
-
Taxonomy of Potamogeton
301
ovate-elliptic,7-35 mm long, 2-13 mm wide, 2-4 timesas long as wide, opaque,subcoriaceous,brightgreen
to darkgreen,5-13-veined, cuneateto roundedat base, obtuseat apex;petiole5-25 mm long, 0.7-1.1 times
as long as the lamina.Stipulesof thefloatingleavesaxillary,convolute,3-15 mm long,translucent,
persistent.
Inflorescencesdimorphicto trimorphic.Peduncleof inflorescencesin the axils of the submergedleaves 1-3
mm long, 0.5-1.0 times as long as the fruitingspike,as thickas the stem;spikeglobose to subglobose,2-5
mm long in fruit,contiguous.Spikeof inflorescencesin the axils of the intermediate
leaves andlowerfloating
leaves subglobose,4-7 mmlong in fruit,contiguous.Peduncleof inflorescencesin the axils of floatingleaves
4-27 mmlong,0.8-2.3 timesas long as the fruitingspike,as thickas the stem;spikesubgloboseto cylindrical,
5-14 mm long in fruit,contiguous.Flowers1-6 in submergedspikes,2-8 in emersedspikes,with4 carpels.
Fruits1.3-2.4 mm long, dorsalkeel distinct,sharp,entire,lateralkeels absent,embryocoiledmorethan1 turn.
Stem anatomy
Stele of trio type, endodermisof 0-type, interlacunar
bundlesabsent,subepidermalbundlespresent,faint,
pseudohypodermis
absent.
Distribution
C andE NorthAmerica.
Note
(1) P. spirillusis closely relatedto P diversifolius.
61. Potamogeton diversifolius Rafinesque, Med. Repos., Hexade 3, 2: 409. 1811.
("diversifolium")
- P diversifoliusRAF.,Med. Repos.,Hexade2, 5: 354. 1808,nom. prov.("diversifolium")
- P. diversifoliusvar.capitatusENGELM.,
Amer.J. Sci. Arts46: 102. 1844, nom. inval.
_ Spirillusdiversifolius(RAF.)NIEUWL.,Amer.Midl.Naturalist3: 18. 1913.
= P capillaceusPOIR.in LAM.,Encycl.Meth.Bot., Suppl.4: 535. 1816. ("capillaceum")
= P dimorphusRAF., Amer.Month.Mag. Crit.Rev. 1: 358. 1817. ("dimorphum")
= P diversifoliusvar.spicatusENGELM.,
Amer.J. Sci. Arts,46: 102. 1844.
= P diversifoliusvar.multidenticulatus
MORONG,
Mem.TorreyBot.Club3(2):48. 1893.("multidenticulatus")
P hybridusvar. [. multidenticulatus
(MORONG)
GRAEBN.
in ENGL.,Pflanzenr.31 (IV.11): 51. 1907.
("multidenticulatus")
-P tricostatusWALLR.ex GRAEBN.in ENGL.,
Pflanzenr.31 (IV.11): 51. 1907, pro syn.
? P spirilliformisHAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 137. 1916.
- P conjungens
HAGSTR.,
Kungl.SvenskaVetenskapsakad.
Handl.55(5): 138. 1916.
- P dimorphoides
HAGSTR.,Kungl.SvenskaVetenskapsakad.
Handl.55(5):263. 1916,prohybr.P diversifolius
(sub P dimorphus)x P pusillus.
- P capillaceusvar.atripesFERNALD,
Rhodora39: 380. 1937.
? P reniacoensisSPARRE,
Bol. Soc. Argent.Bot. 6(2): 107. 1956.
Description
Rhizomefiliformto slender,compressed,perennial.Stem richlybranched,filiformto slender,compressedto
subterete,annual;axillarydormantturionsdeveloping.Submergedleaves sessile, linear,(10-)20-65(-l 10)
mm long, (0.2-)0.4-1.0(-l.5) mm wide, 20-180(-280) times as long as wide, brightgreen to darkgreen,
1(-3)-veined,withoutadditionalsclerenchymatous
strands,not borderedby a marginalvein, with or without
narrowrowsof lacunaeborderingthe midrib,entireat margins,straightat base,narrowlyobtuseto acuminate
at apex. Stipulesof the submergedleaves adnate,convolute,2-6(-18) mm long, fused with the leaves for
0.3-4.0(-7.0) mm, translucent,persistent.Intermediate
leavesoftenpresent.Floatingleaves shortlypetiolate;
laminaoblongto ellipticor orbicular-elliptic,
(7-)13-40 mmlong,(2-)4-17(-20) mm wide,2-4 timesas long
as wide, opaque,subcoriaceous,brightgreento darkgreen,(3-)5-l5(-17)-veined, cuneateto roundedat base,
acuteto roundedat apex;petiole2-40 mm long, 0.6-1.2 times as long as the lamina.Stipulesof the floating
leaves axillary to slightly adnate, convolute, (2-)7-25 mm long, translucent,persistent.Inflorescences
dimorphic.Peduncleof inflorescencesin the axils of the submergedleaves 1-8 mm long, 0.5-1.5 times as
long as the fruitingspike,as thickas the stem;spikegloboseto subglobose,2-6 mm long in fruit,contiguous.
Peduncleof inflorescencesin the axils of floatingleaves3-32 mm long, 0.8-1.4 times as long as the fruiting
spike,as thickas the stem;spike subgloboseto cylindrical,3-28 mm long in fruit,contiguous.Flowers1-8
302
G. Wiegleb & Z. Kaplan
in submergedspikes,4-30 in emersedspikes,with4 carpels.Fruits0.9-2.0(-2.2) mmlong,dorsalkeel distinct,
sharp,dentate,lateralkeels usuallypresent,entireto dentate,embryocoiled morethan 1 turn.
Stem anatomy
Stele of triotype, endodermisof 0-type, interlacunar
bundlesabsentor rarelypresent,subepidermal
bundles
absentor a few present,pseudohypodermis
absentor partlypresent,1-layered.
Distribution
NorthAmerica,SE SouthAmerica.
Note
(1) DespitetheirremoteoccurrenceSouthAmericanplants(likee.g. P.spirilliformis)
areregardedas conspecific
with NorthAmericanones. However,theirvariationis insufficientlyknown.
62. Potamogeton bicupulatus FERNALD,
Mem. Amer. Acad. Arts Sci. 17: 112. 1932.
P diversifolius var. trichophyllus MORONG,
Mem.Torrey Bot. Club 3(2): 49. 1893.
_ P hybridusvar.y. trichophyllus(MORONG)
GRAEBN.
in ENGL.,Pflanzenr.31 (IV.11): 51. 1907.
Description
Rhizomefiliform,compressed,perennial.Stemsparinglyto richlybranched,filiform,terete,annual;specialized
dormantturionsnot developing.Submergedleavessessile, setaceous,30-1 10 mmlong,0.08-0.40(-0.50) mm
wide, (140-)190-500(-600) times as long as wide, brightgreento darkgreen, 1-veined,withoutadditional
sclerenchymatous
strands,not borderedby a marginalvein, withoutrows of lacunaeborderingthe midrib,
entireat margins,straightat base,acuminateat apex.Stipulesof the submergedleavesadnate,convolute,2-12
mm long, fused with the leaves for 0.3-3.5 mm, translucent,persistent.Intermediateleaves often present.
Floatingleaves shortlypetiolate;laminaoblongto broadlyelliptic,6-23(-28) mm long, 2-11 mm wide, 2-5
times as long as wide, opaque,subcoriaceous,brightgreento darkgreen,5-15-veined,cuneateto roundedat
base,acuteat apex;petiole5-35 mm long, 0.8-1.4 timesas long as the lamina.Stipulesof the floatingleaves
axillary,convolute,3-1 1 mmlong,translucent,
persistent.Inflorescences
dimorphic.Peduncleof inflorescences
in the axils of the submergedleaves 1-10 mm long, 0.5-1.5 timesas long as the fruitingspike,as thickas the
stem;spikeglobose to subglobose,2-7 mm long in fruit,contiguous.Peduncleof inflorescencesin the axils
of floating leaves 3-22 mm long, 1.0-1.9 times as long as the fruitingspike, as thick as the stem; spike
subgloboseto cylindrical,3-14 mm long in fruit,contiguous.Flowers 1-8 in submergedspikes, 2-10 in
emersedspikes, with 4 carpels.Fruits(l.l-)1.6-2.0 mm long, dorsalkeel distinct,sharp,entireto dentate,
lateralkeels usuallypresent,entireto dentate,embryocoiled morethan1 turn.
Stem anatomy
Not seen.
Distribution
C andE NorthAmerica.
Note
(1) P bicupulatusis closely relatedto P diversifolius andmay be regardedas an extrememorphotypeof that
speciesundera widerspecies concept.
63. Potamogeton vaginatus TURCZANINOW,
Bull. Soc. Imp. Naturalistes Moscou 27(3): 66. 1854.
-P. vaginatusTURCZ.,
Bull. Soc. Imp.NaturalistesMoscou 11(1): 102. 1838, nom. nud.
P pectinatus subsp. vaginatus (TURCZ.)MAGNIN,Bull. Soc. Bot. France 43: 447. 1896.
_ P.pectinatus var. vaginatus (TURCZ.)ASCH.et GRAEBN.,Synops. Mitteleur. Fl. 1: 351. 1897.
Stuckeniavaginata(TURCZ.)
HOLUB,
Folia Geobot.Phytotax.19(2):215. 1984.
Coleogetonvaginatus(TURCZ.)
LESet R.R. HAYNES,
Novon 6(4): 390. 1996.
= P moniliformis H. ST. JOHN,Rhodora 18: 130. 1916.
= P vaginatus var. canadensis HAGSTR.,
Kungl. Svenska Vetenskapsakad. Handl. 55(5): 36. 1916.
- P. canadensis HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 36. 1916, nom. prov.
Description
Rhizomeslenderto robust,terete,perennial,with apicaltubers.Stem richly branched,with severalrenewal
shootsspringingfromone node, slender,terete,annualto perennial,wintergreen;specializeddormantturions
not developing.Submergedleaves sessile, filiformto linear,20-120(-150) mm long, 1-2 mm wide, 20-130
Taxonomy of Potamogeton
303
times as long as wide, olive green to dark green, often with a greyish tinge, 1-3-veined, lateralveins
inconspicuous,withair channelsborderingthe midrib,entireat margins,straightat base,obtuseto sometimes
slightlysubretuseat apex.Floatingleavesalwaysabsent.Stipulesadnate,connate,20-50(-70) mmlong, 2-10
mm wide, fused with the leaves for 17-45(-65) mm, persistent.Peduncles30-150(-200) mm long, 1.5-4.5
timesas long as the fruitingspike,as thickas the stem.Spikescylindrical,25-70 mm long in fruit,contiguous
to distant.Flowers14-16(-20), with4 carpels.Fruits3.0-3.8 mm long, dorsalkeel indistinct.
Stem anatomy
Stele of trio or four bundles type, endodermisof U-type, interlacunarbundlespresent in (3-)4 circles,
subepidermal
bundlesabsent,rarelya few present,pseudohypodermis
present,1-2-layered.
Distribution
Circumboreal;
N Europe,N Asia, N NorthAmerica.
Hybrids
66 x 63. P. xfennicus HAGSTR.,
Kungi.Svenska Vetenskapsakad.Handl.55(5): 24. 1916.
[= P.filiformisx P. vaginatus]
-Stuckenia xfennica (HAGSTR.)HOLUB,Preslia 69: 364. 1997.
68 x 63. P. xbottnicus HAGSTR.,
Kungi.Svenska Vetenskapsakad.Handl.55(5): 52. 1916.
[= P pectinatusx P vaginatus]
Stuckenia xbottnica (HAGSTR.)HOLUB,Preslia 69: 364. 1997.
Note
(1) P. vaginatusis a well defined species which, until recently,has been sometimesconfusedwith its own
hybridsand wintergreenformsof P. pectinatus.
64. Potamogeton subretusus HAGSTROM,
Kungl. Svenska Vetenskapsakad. Handl. 55(5): 30.
1916.
= Stuckenia subretusa (HAGSTR.)HOLUB,Preslia 69: 364. 1997.
Description
Rhizomeslender,terete,perennial,withapicaltubers.Stemsparinglyto richlybranched,slender,terete,annual
to perennial;specializeddormantturionsnot developing.Submergedleaves sessile, filiformto linear,20-100
mmlong,0.6-1.3(-1.5) mm wide, 25-90 timesas long as wide,olive greento darkgreen,oftenwitha greyish
tinge,3-5-veined,lateralveins inconspicuous,withairchannelsborderingthemidrib,entireat margins,straight
at base, obtuse to distinctly subretuseat apex. Floating leaves always absent. Stipules adnate,connate,
20-30(-40) mm long, 1.5-4.0 mm wide, fused with the leaves for 18-26(-35) mm, persistent.Peduncles
100-170(-200) mm long, 2-5 times as long as the fruitingspike, as thick as the stem. Spikes cylindrical,
20-50 mm long in fruit,contiguousto distant.Flowers6-16, with 4 carpels.Fruits2.2-3.0 mm long, dorsal
keel indistinct.
Stem anatomy
Steleof 4 bundlestype,endodermisof U-type,interlacunar
bundlespresentin 1 incompletecircle,subepidermal
bundlesabsent,pseudohypodermis
absent.
Distribution
NE Europe,N Asia, NW NorthAmerica.
Note
(1) P. subretususis closely relatedto P vaginatusandin the futuremaybe regardedas an extrememorphotype
of thatspecies.
65. Potamogeton recurvatus HAGSTROM,
Kungi. Svenska Vetenskapsakad. Handl. 55(5): 37.
1916.
Description
Rhizomeslenderto robust,terete,perennial,with apical tubers.Stem branched,slender,terete,annualto
perennial;specializeddormantturionsnot developing.Submergedleaves sessile, linear,stronglyrecurvedat
the top, (40-)50-120(-500) mm long, 1.0-1.6 mm wide, 30-100 timesas long as wide, brightgreento olive
green,3-veined,lateralveins inconspicuous,withairchannelsborderingthe midrib,entireat margins,straight
304
G. Wiegleb & Z. Kaplan
at base, obtuseat apex. Floatingleaves alwaysabsent.Stipulesadnate,connate,7-140 mm long, fused with
the leaves for 5-120 mm, persistent.Peduncles20-50 mm long, 1-2 times as long as the fruitingspike,as
thickas thestem.Spikescylindrical,contiguousto distant.Flowerandcarpelnumbersunknown.Fruits3.0-3.5
mm long, dorsalkeel indistinct.
Stem anatomy
Stele of four bundlestype, endodermisof U-type,interlacunar
bundlespresentin 1-2 circles, subepidermal
bundlespresent,pseudohypodermis
present,1-layered.
Distribution
C Asia.
Note
(1) P recurvatushas been describedon the basis of a few specimensonly. It is insufficientlyknown,but
perhaps related to P vaginatus.
66. Potamogeton filiformis PERSOON,Syn. Pi. 1: 152. 1805. ("filiforme")
P setaceus SCHUMACH.,
Enum. P1. 1: 51. 1801, nom. illeg. ("setaceum"), non L. 1753.
P pectinatus var. P. setaceus [SCHUMACH.]
C. HARTM,Handb. Skand. Fl. ed. 11. 437. 1879.
P pectinatus subsp. filiformis (PERS.)HOOK.f., Stud. FH.Brit. Isl. 374. 1870.
Stuckenia filiformis (PERs.) BORNER,Fl. Deutsche Volk 713. 1912.
Spirillusfilifonnis (PERS.)NIEUWL.,Amer. Midi. Naturalist 3: 18. 1913.
Coleogetonfiliformis (PERS.)LES et R.R. HAYNES,Novon 6(4): 390. 1996.
= P borealis RAF., Med. Repos., Hexade 3, 2: 409. 1811.
- P borealis RAF., Med. Repos., Hexade 2, 5: 354. 1808, nom. prov.
P filiformis var. borealis (RAF.)H. ST. JOHN,Rhodora 18: 134. 1916.
Stuckenia borealis (RAF.)HOLUB,Preslia 69: 364. 1997.
= P fasciculatus WOLFG.in SCHULT.et SCHULT.
f., Mant. 3: 364. 1827.
- P filiformis var.fasciculatus (WOLFG.)G. FISCH.,Ber. Bayer. Bot. Ges. 11: 132. 1907.
= P strictus PHIL.,Fl. Atacam. 50. 1860. [non vidimus]
= P marinusvar.alpinusBLYTr,Norges Fl. 1: 370. 1861.
P filiformis var. P. alpinus (BLYrF) ASCH.et GRAEBN.,Synops. Mitteleur. Fl. 1: 353. 1897.
Coleogetonfiliformis subsp. alpinus (BLYTr)LES et R.R. HAYNES,Novon 6(4): 390. 1996.
= P marinus var. occidentalis J.W. ROBBINSin S. WATSON,U.S. Geol. Explor. Fortieth Parallel 5(Botany):
338. 1871.
P filiformis var. occidentalis (J.W. ROBBINS)MORONG,Mem. Torrey Bot. Club 3(2): 51. 1893.
P interior RYDB., Agric. Exp. Stat. Agric. Coll. Colorado Bull. [Fl. Colorado] 13. 1906. ("1905")
Coleogetonfiliformis subsp. occidentalis (J.W. ROBBINS)LES et R R. HAYNES,Novon 6(4): 390. 1996.
Stuckenia interior (RYDB.) HOLun, Preslia 69: 364. 1997.
= P marinus var. macounii MORONGex MACOUN,Catal. Canad. P1. 4: 88. 1888. ("Macounii")
P filiformis var macounii (MORONGex MACOUN)MORONG,Mem. Torrey Bot. Club 3(2): 50. 1893.
= P aulacophyllus K. SCHUM.in MART.,Fl. Bras. 3, 3: 696. 1894. ("aulacophyllum")
= P juncifolius A. KERN.ex C. FRITSCH,Verh. K. K. Zool.-Bot. Ges. Wien, 45(1895): 366. 1896.
_ P filiformis subsp. juncifolius (A. KERN.ex C. FRITSCH)ASCHERS.et GRAEBN.,Synops. Mitteleur. Fl.
ed. 2. 1: 544. 1913.
P.filiformis var.juncifolius (A. KERN.ex C. FRITSCH)SUESS.in HEGI,Ill. Fl. Mitt.Europ. ed. 2. 1: 202.
1936.
= P strictus var. magellanicus HAGSTR.,Kungl. Svenska Vetenskapsakad.Handl. 55(5): 27. 1916.
= ? P. rostratus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 27. 1916.
= P austrosibiricus KASCHINAin KRASNOB.et SAFONOVA,
Novoe Fl. Sibiri 243. 1986. ("austrosibiricus")
= P applanatusY.D. CHEN,Acta Hydrobiol. Sin. 11(3): 230. 1987.
= P filiformis var. applanatus (Y.D. CHEN)Q.Y. Li, J. Wuhan Bot. Res. 10(1): 13. 1992.
= ? P punense GALAN-MERA,Phytologia 64(6): 495. 1988.
Description
Rhizome slender, terete, perennial, with apical tubers. Stem unbranchedto sparingly branched, slender, terete,
annual to perennial; specialized dormant turions not developing. Submerged leaves sessile, filiform,
Taxonomy of Potamogeton
305
30-175(-240) mm long, 0.3-1.2(-1.9) mnm
wide, (50-)100-300 times as long as wide, olive greento dark
green,sometimeswith a greyishtinge, 3-veined,lateralveins inconspicuous,with air channelsborderingthe
midrib,entireat margins,straightat base, obtuseto subacuteat apex.Floatingleaves alwaysabsent.Stipules
adnate,connate,8-27(-55) mmlong,fusedwiththeleavesfor3-1 9(-50) mm,persistentto decaying.Peduncles
(25-)50-190(-220) mm long, 2-5(-6) times as long as the fruitingspike, as thick as the stem, terminalon
primarystem or on first orderrenewalshoots.Spikescylindrical,13-75 mm long in fruit,markedlydistant.
Flowers4-1 1, with 4(-6) carpels.Fruits(1.9-)2.2-2.8(-3.2) mm long, dorsalkeel indistinct.
Stem anatomy
Stele of fourbundlesor rarelyoblongtype,endodermisof U-type,rarely0-type, interlacunar
bundlespresent
in 1(-3) incompletecircles, subepidermal
bundlesabsent,pseudohypodermis
present,1-2-layered.
Distribution
Europe,W, C andN Asia, NorthAmericaandSouthAmerica.
Hybrids
66 x 63. P. xfennicus HAGSTR.,Kungi.Svenska Vetenskapsakad.Handl.55(5): 24. 1916.
[= P filiformisx P vaginatus]
66 x 68. P xsuecicus K. RICHT.,
Pi. Eur. 1: 15. 1890.
[= P.filiformisx P pectinatus]
_ Stuckeniaxsuecica(K. RICHT.)HOLUB,Preslia69: 364. 1997.
Notes
(1) P filiformisis a widespreadpolymorphicspecies.It includesseveralaberrant
morphotypeslikeP rostratus.
(2) P. strictusdiffers from the type in some anatomicalcharactersof stem structure(e.g. stele regularlyof
oblong type). Despite being geographicallyremotefrom the rest of the species, no furtherdistinguishing
characterwas found.
67. Potamogeton amblyphyllus C.A. MEYER,Beitr. Pflanzenk. Russ. Reiches 6: 10. 1849.
("amblyophyllus")
= P pectinatusprolesamblyphyllus(C.A. MEY.)GRAEBN.in ENGL.,Pflanzenr.31 (IV.11): 125. 1907.
= Stuckeniaamblyphylla(C.A. MEY.)HOLUB,Preslia69: 364. 1997.
? P pamiricusBAAGOE,Vidensk.Meddel.DanskNaturhist.Foren.Kjobenhavn1903: 182. 1903.
Description
Rhizomeslender,terete,perennial,with apicaltubers.Stemunbranched
to sparinglybranched,slender,terete,
annualto perennial;specializeddormantturionsnot developing.Submergedleaves sessile, filiform,30-120
mm long, 1-3 mm wide, 20-50 times as long as wide, olive green to darkgreen, 3-veined, lateralveins
inconspicuous,with air channelsborderingthe midrib,entireat margins,straightat base, obtuse at apex.
Floatingleaves alwaysabsent.Stipulesadnate,connate,10-35 mm long, fusedwith the leaves for 5-20 mm,
persistent.Peduncles50-80 mm long, 1.5-3.0 timesas long as the fruitingspike,as thickas the stem.Spikes
cylindrical,30-35 mmlong in fruit,distant.Flowers9-12, with4 carpels.Fruits(2.8-)3.0-3.5 mmlong,dorsal
keel indistinct.
Stem anatomy
Stele of four bundles type, endodermisof U-type, interlacunarbundles present as 1 incompletecircle,
subepidermal
bundlesabsent,pseudohypodermis
present,1-2-layered.
Distribution
SW andC Asia.
Note
(1) P amblyphyllus
is closely relatedto P filiformis.It comprisesmorerobustformsof a restrictedgeographical
area. P pamiricus is included in this concept of P amblyphyllus.
68. Potamogeton pectinatus LINNAEUS,
Sp. Pi. 127. 1753. ("pectinatum")
= Stuckenia pectinata (L.) BORNER,Fl. Deutsche Volk 713. 1912.
= Spirilluspectiniformis[L.] NIEUWL.,Amer.Midl.Naturalist3: 18. 1913.
306
G. Wiegleb & Z. Kaplan
- Coleogeton pectinatus (L.) DOSTAL,Sezn. Cevn. Rostl. Kvet. Ceskosl. 309. 1982, nom. inval.; DOSTAL,
Folia Mus. Rer. Natur. Bohem. Occid., Bot., 21: 15. 1984, nom. inval.
Coleogeton pectinatus (L.) LES et R.R. HAYNES,Novon 6(4): 390. 1996.
= P marinusL., Sp. PI. 127. 1753. ("marinum")
= P interruptusKIr.in SCHULT.,Oesterr. Fl. ed. 2. 1: 328. 1814.
-P pusillus [var.] P. interruptus (KIT.) J. PRESLet C. PRESL,Fl. (tech. 37. 1819.
P. pectinatus var. interruptus (KiT.) ASCH.,Fl. Brandenb. 1: 666. 1864.
= P pectinatusproles interruptus(KIr.)GRAEBN.in ENGL.,Pflanzenr. 31 (IV. 11): 124. 1907.
Spirillusinterruptus(KIT.)NIEUWL.,Amer. Midl. Naturalist 3: 18. 1913.
= P tenuifoliusKUNTH in HUMB.,BONPL.et KuNTH, Nov. Gen. Sp. P1. 1, ed. 40: 370 [et ed. f: 297]. 1815,
nom. illeg. ("tenuifolium"), non Raf. 181 1.
= P angustissimusKUNTH in HUMB., BONPL.et KUNTH,Nov. Gen. Sp. P1. 1, ed. 4?: 370 [et ed. f?: 297].
1815. ("angustissimum")
= P vaillantii ROEM.et SCHULT.,Syst. Veg. ed. 16. 3: 514. 1818. ("Vaillantii")
_ P pectinatus [var.] ("spielart") a. latifolius G. MEY.,Chloris Han. 526. 1836.
= P siculus J. PRESLin BERCHT.et J. PRESL,Rostlinar 1,.fasc. Zabnjkowite 21. 1821. ("siculum")
= P pectinatusvar. P. dichotomusWALLR.,Sched. Crit. 1: 68. 1822.
= P pectinatusvar. a. protensusWALLR.,Sched. Crit. 1: 67. 1822.
= P pectinatusvar. Y. scopariusWALLR.,Sched. Crit. 1: 68. 1822.
P pectinatus var. diffusus HAGSTR.,Kungl. Svenska Vetenskapsakad. Handl. 55(5): 46. 1916, nom. illeg.
P pectinatusproles scoparius(WALLR.)GRAEBN.in ENGL.,Pflanzenr. 31 (IV.11): 125. 1907.
P diffusus[HAGSTR.]HERTER,Revista Sudamer. Bot. 6(5-6): 132. 1940. [non vidimus]
= P zosteraceus FR.,Novit. Fl. Suec. ed. 2. 51. 1828.
= P pectinatus var. zosteraceus (FR.)CASP., Schriften Phys.-Okon. Ges. Konigsberg 29: 89. 1888.
= P pectinatusproles zosteraceus(FR.) GRAEBN.in ENGL.,Pflanzenr. 31 (IV.1 1): 126. 1907.
= P pectinatus [subsp.] P. fluviatilis SCHUBL.et G. MARTENs,Fl. Wurttemb. 112. 1834.
= P drupaceus0. LANG,Flora29(30):472. 1846.
= P flabellatusBAB., Man.Brit.Bot. ed. 3. 343. 1851.
P pectinatussubsp. flabellatus(BAB.) HOOK.f., Stud. Fl. Brit. Isl. 374. 1870.
_ P pusillus subsp. flabellatus (BAB.) HOOK.f., Stud. Fl. Brit. Isl. ed. 3. 436. 1884.
? P pectinatusvar.mongolicusA. BENN.,J. Bot. 32: 203. 1894.
? P pectinatusproles mongolicus(A. BENN.)GRAEBN.in ENGL.,Pflanzenr. 31 (IV.11): 125. 1907.
? P pectinatus subsp. mongolicus (A. BENN.)VOLOB.,Sibir. Biol. Zhurn. 1991(5): 75. 1991.
= P columbianus SUKSDORF,Deutsche Bot. Monatsschr. 19: 92. 1901.
= P livingstoneiA. BENN.in DYER,Fl. Trop. Afr. 8: 223. 1901. ("Livingstonei")
= P vaginatusvar. helveticusG. FISCH.,Ber. Bayer. Bot. Ges. 11: 134. 1907.
= P vaginatussubsp. helveticus(G. FISCH.)SCHINZet THELL.,Fl. Schweiz ed. 4. 1: 32. 1923.
= P helveticus (G. FIsCH.) W. KOCH in W. KOCHet G. KUMMER,Mitt. Naturf. Ges. Schaffhausen
-
1923-1924(3):38. 1924.
P helveticus (G. FISCH.)E. BAUMANN,Veroff. Geobot. Inst. ETH Stiftung Rubel Zurich 3(5): 594. 1925.
[isonymum]
P pectinatus var. helveticus (G. FISCH.)GLUCKin PASCHER,Susswasserflora 15: 62. 1936.
Stuckenia helvetica (RAF.)HOLUB,Preslia 69: 364. 1997.
- P helveticusvar.balatonicusGAMS,Arch.Balaton.1: 30.
1926.
P balatonicus (GAMS)So0, Arch. Balaton. [= Magyar Biol. Kutat6int. Munkai], 2: 136. 1928.
P.pectinatus subsp. balatonicus (GAMS)S06, Magyar Biol. Kutat6int. Munkai 8(1935-1936): 235. 1936.
- Coleogetonpectinatussubsp. balatonicus(GAMS)DoSTAL,Sezn. Cevn. Rostl. Kvet. C-eskosl. 309. 1982,
nom inval.; (GAMS)DoSTAL, Folia Mus. Rer. Natur. Bohem. Occid., Bot., 21: 15. 1984, nom. inval.
-? P pectinatusvar.gracilisKUZMINet SKVORTZOV
in BARANOVet SKVORTZOV,
Diagn. P1.Nov. Min. Cogn.
Mandsch. 1. 1943.
P macrocarpus DOBROCHOT.,
Bot. Mat. Gerb. Bot. Inst. Akad. Nauk SSSR [= Not. Syst. Herb. Inst. Bot.
Acad. Sci. URSS] 14: 70. 1951.
-P intramongolicus Y.C. MA, ActaBot. Bor.-Occid. Sin. 3(1): 8. 1983, nom. inval.; YC. MA, Fl. Intramongolica
7: 12. 1983, nom. inval.
Taxonomy of Potamogeton
307
- P acifolius Y.C. MA, Acta Bot. Bor.Occid. Sin. 3(1): 10. 1983, nom. inval.
= P pectinatus subsp. chakassiensis KASCHINAin KRASNOB.et SAFONOVA,
Novoe o Fl. Sibiri 245. 1986.
P. chakassiensis (KASCHINA)VOLOB.,Sibir. Biol. Zhum. 1991(5): 75. 1991.
Description
Rhizomeslenderto very robust,terete,perennial,with apicaltubersat the end of the growingseason.Stem
sparinglyto richly branched,filiform to slender,terete,annualto perennial,summergreenor wintergreen;
specializeddormantturionsnot developing,sometimeswith winterbudsas axillaryleafy shoots.Submerged
leaves sessile, filiformto linear,22-125(-200) mm long, 0.2-4.0 mm wide, 24-160(-200) times as long as
wide, brightgreen to olive green, 3-5-veined, lateralveins inconspicuous,with air channelsborderingthe
midrib,entireat margins,straightat base, acuminateto acuteat apex, sometimesthe broadestleaves obtuse.
Floatingleaves always absent.Stipulesadnate,convolute,10-70 mm long, fused with the leaves for 8-65
mm,persistent.Peduncles20-130(-450) mmlong, 1.5-5.0(-10.0) timesas long as the fruitingspike,as thick
as the stem, flexible. Spikes cylindrical,13-60 mm long in fruit,contiguousat first, laterdistant.Powers
(4-)8-14, with4 carpels.Fruits3.3-4.7(-5.1) mm long, dorsalkeel indistinct.
Stem anatomy
Stele of fourbundles,oblongor rarelyI circulartype, endodermisof U-type,interlacunar
bundlespresentin
1 more or less complete circle, subepidermalbundles absent,rarelypresent,pseudohypodermis
present,
1-2-layered.
Distribution
Cosmopolitan;Europe,Africa,Asia, Australia,NorthAmericaand SouthAmerica.
Hybrids
? 25 x 68. P. xnomotoensis KADONO
et T. Noguchi, Acta Phytotax.Geobot. 42(2): 175. 1991, pro sp.
[= ? P natansx P. pectinatus]
68 x 63. P. xbottnicus HAGSTR.,
Kungi.Svenska Vetenskapsakad.Handl.55(5): 52. 1916.
[= P pectinatusx P vaginatus]
66 x 68. P. xsuecicus K. RICHT.,
PI. Eur.1: 15. 1890.
[= P filiformisx P pectinatus]
Notes
(1) P pectinatusis an extremelypolymorphicspecies with numerouslocal and regionalforms as well as
extremeecomorphoses.
(2) RobustwintergreenformscalledP helveticusareoccasionallyfoundin riversandlargeclear-waterlakes.
Theircharactersare not stablewhen transplantated
into cultivationand they are producedrepeatedlyunder
specialecologicalcircumstances.The exact relationshipof these similarplantsknownfrom distantareasis
unknown.
(3) P chakassiensiscomprisesa set of formswith stipulesand leaves considerablylongerthanin the type.
However,they do not deservespecificrank(KAPLAN
1995).
69. Potamogeton striatus Ruiz et PAVON,Fl. Peruv. Chil. 1: 70. 1798. ("striatum")
P pectinatus var striatus (RUIz et PAV.)HAGSTR.,Kungi. Svenska Vetenskapsakad. Handl. 55(5): 51.
1916.
Coleogeton striatus (RuIz et PAV.)LES et R.R. HAYNES,Novon 6(4): 390. 1996.
Stuckenia striata (RuIz et PAV.)HOLUB,Preslia 69: 364. 1997.
= P pectinatus var. latifolius J.W. ROBBINSin S. WATSON,U. S. Geol. Explor. Fortieth Parallel 5(Bot.): 338.
1871, nom. illeg., non G. MEY1836.
P latifolius [J.W. ROBBINS]MORONG,Mem. Torrey Bot. Club 3(2): 52, tab. 59. 1893. nom. illeg., non
SLOBODA1852.
P filiformis var. latifolius [J.W. ROBBINS]REVEALin CRONQUIST
et al., Intermountain Fl., Vasc. P1.
Intermountain
West,USA 6: 26. 1977.
P latiorHOLUB,
Folia Geobot.Phytotax.18(2):204. 1983.
= P australis F. PHIL.,Anal. Mus. Nac. Chile 2(8): 95. 1891. [non vidimus]
= P dissimilis A. BENN., J. Bot. 48: 150. 1910.
308
G. Wiegleb & Z. Kaplan
Description
Rhizomeslender,terete,perennial,withoutapicaltubers.Stem sparinglyto richlybranched,slender,terete,
annualto perennial;specializeddormantturionsnot developing.Submergedleavessessile, linear,50-210 mm
long, 0.4-5.1 mm wide, 35-150 times as long as wide, brightgreento darkgreen,3-7-veined, lateralveins
inconspicuous,with air channelsborderingthe midrib,entireat margins,straightat base, acute to obtuseat
apex,sometimesthe broadestleaves obtuse.Floatingleaves alwaysabsent.Stipulesadnate,convolute,12-34
mm long, fused with the leaves for 9-28 mm,persistent.Peduncles12-54 mm long, 0.8-2.0 timesas long as
the fruitingspike, as thick as or slightlythinnerthanthe stem. Spikescylindrical,17-60 mm long in fruit,
contiguousat the beginning,distantlater.Flowers7-16, with 4 carpels.Fruits3.0-3.9 mm long, dorsalkeel
indistinct.
Stem anatomy
Stele of complexoblongtypeor rarelycirculartype,endodermisof U-type,rarely0-type, interlacunar
bundles
presentin 1-2 incompletecircles, subepidermal
bundlesabsent,pseudohypodermis
1(-2)-layered.
Distribution
W andSW NorthAmenrcaandSouthAmerica.
Note
(1) P striatus has often been treated as a subunit of P. pectinatus. Even though both species are closely related
the differentialcharactersseem to be constantthroughoutthe rangeof P. striatus. The separatepositionof the
species has been recentlysupportedby an isozymestudy(HOLLINGSWORTH
et al. 1996).The relationshipto
morphologically
similarplantsknownfromEuropeandAsia, hereincludedin P.pectinatus, has to be clarified.
CONCLUSIONS
In the preceeding paragraphsa large bulk of informationregardingthe description and
identification of Potamogeton species has been compiled. The present treatment can be
summarizedas follows:
(1) A total of 69 species are described. In several cases it was easier to constructa key to
distinguishamong those species than to present a really comprehensivedescriptioncovering
all important characters. Not all of the species listed fully meet the requirementsof a
"sufficiently known species". Nevertheless, we are convinced that they actually exist as
biological entities. The truenumberof species may be lower, as ca. 10 species can be regarded
as candidatesto be lumped into other widespreadpolymorphic species.
(2) Several taxa otherwise recognized have been excluded from the treatmentas they are
obvious ecomorphosesor extreme morphotypesof other well-known species. The numberof
species in Potamogetonis generallyoverestimated.Estimatesof 90-120 species areunjustified
or based on a narrowerspecies concept. We think that in the context of the species concept
outlined above 69 is approximatelythe right order of magnitude to be expected worldwide
for Potamogetonspecies. We do not believe thattoo many "question-markspecies" will prove
to be taxa in their own right in the future.Three species may lie undescribedin herbaria(one
from Madagascar,New Guinea, and South America respectively).
The question marks in the synonym lists, and in particularthe notes, show that there is a
lot of work to be done in Potamogeton taxonomy,which has been hamperedby the fact that
authenticseed materialfrom many partsof the world is difficult to obtain.Furthermore,many
species are not easy to keep in cultivation and show only minimal development of
morphologicalcharacters.Necessary work includes:
(1) Extensive field surveys and collection of specimens in the Southern Hemisphere in
orderto bringthe total numbersof specimens comparableto thatin the NorthernHemisphere.
(2) Typification of all relevant names. "Relevant" refers to all species and hybrids
recognized here, all taxa contributingbasionyms, and all taxa being importantfor applying
the priorityrule.
Taxonomy of Potamogeton
309
(3) Chromosomecounts on well identified specimens, both from the NorthernHemisphere
but in particularfrom the SouthernHemisphere.
(4) Experimentalcultivation in order to reveal the actual range of phenotypic plasticity.
(5) Crossing experiments to verify or rule out assumed hybridization.
(6) Molecular approacheson the affinity of species and species groups as well as on the
verification of hybrids.
Acknowledgements:We thankthe keepersof all herbariawho contributedloansto this studyor who allowed
us to work in their institutions.K. van de Weyer(Nettetal)communicatedimportantinformationon some
CentralEuropeantaxa and S.E. Papassotiriou(Sydney)on some Australianones. K. Kubitzki(Hamburg)
J. Stepanek
criticallyreada preliminaryversionof the text.We arealso gratefulto C.D. Preston(Huntingdon),
(Pruhonice)andC.D.K.Cook (Zurich)for reviewingandcommentingon the manuscript.Z. Kaplanhasbeen
financiallysupportedby grantno. 206/98/1539of the GrantAgency of the CzechRepublic.
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EnCl.Appendixpp. 311-316
311
Taxonomy of Potamogeton
APPENDIX
Index of scientific names
Only final epithetswith authorshipare includedinto the index. Nomenclaturalsynonymswith the same final epithetare
representedby theirbasionymonly.Epithetsof correctnames(or theirbasionyms)of acceptedspecies areprintedin bold.
Supraspecific names
ColeogetonRCHB.
GroenlandiaJ. GAY.
Potamogeton L.
StuckeniaBORNER
243, 244
243
241-245, 247, 259, 270, 283, 308
243-244
Specific and infraspecific names in Potamogeton
acifolius Y.C.MA
307
acuminatus FIEBER
292
acuminatus SCHUMACH.
274
acuminatus WAHLENB.
279
acutifolius FIEBER
284
acutifolius LINK
243, 250, 287, 288, 292-293
acutus SCHLTDL.
291
affinis A. BENN.
275
256
affinis BOENN.ex CHAM.et SCHLTDL.
alatofructus A. BENN.
278
alatus KoIDZ.
268
alpinonatans F.W. SCHULTZ
256
alpinus BALB. 242, 243, 247, 248, 253, 256, 263, 264,
274, 277, 278, 280, 285
alpinus BLYTT
304
amblyphyllus C.A. MEY.
249, 305
americanus A. BENN.
289
americanus CHAM.et SCHLTDL
269
amphibius FR.
274
amphibius HAGSTR.
260
amplifolius TucK.
248, 254, 261
anadyrensis V.N. VASSIL.
290
anglicus HAGSTR.
256
anguillanus KOIDZ.
278
angustifolius FIEBER
297
angustifolius G. MEY.
266
angustifolius GRAEBN.
279
angustifolius J. PRESL
245, 274, 275, 277, 289
angustissimus HAGSTR.
273
angustissimus KUNTH
306
annulatus BELLARDI
263
antaicus HAGSTR.
292
apertus MIKI
293, 299
apicalis HAGSTR.
262
applanatus Y.D. CHEN
304
argentinus A. BENN
292
aschersonii A. BENN.
292
asiaticus A. BENN.
298
atripes FERNALD
301
attenuatus A. CAMUS
268
attenuatus HAGSTR.
286, 293
augustanus BALB.
aulacophyllus K. SCHUM.
australiensis A. BENN.
australis F. PHIL.
australis KIRK ex A. BENN.
austriacus GAND,
austrosibiricus KASCHINA
azoricus A. BENN.
baagoei
306
285, 298
FRYER
292, 294
275
292, 294
243, 250, 302
FERNALD
276
276
258, 277
FRYER
277, 286
279
304
HAGSTR.
brasiliensis A. BENN. ex GRAEBN.
brevifolius CELAK.
bunyonyiensis DENNY et LYE
bupleuroides FERNALD
burkartii HORN ex TUR
DANDY
273
292
biwaensis MIKI
borealis LAEST.
borealis RAF.
cadburyae
304
297
biformis HAGSTR.
biformoides PAPCHENKOV
bottnicus
284
261
berchtoldii FIEBER
berolinensis ASCH. et GRAEBN.
berteroanus PHIL.
billupsii
307
282
275
babingtonii A. BENN.
badioviridis HAGSTR.
badius HAGSTR.
baenitzii GAND.
balatonicus GAMS
bicupulatus
304
254, 258, 259, 283
264
A. BENN.
bennettii
276
et G.
TAYLOR
californicus MORONG
canadensis HAGSTR.
canariensis LINK
capensis CHAM. ex KUNTH
capensis SCHEELE ex A. BENN.
capensis SCHEELE ex HAGSTR.
capensis T. DURAND et SCHINZ
capillaceus POIR.
capillaris GAUDIN
303, 307
272
279
265
278
294
275, 285
295
302
269
264
273
273
264
301
297
G. Wiegleb & Z. Kaplan
312
capitatusENGELM.
carinatusKUPFFER
caspary KOHTS
caudatusSEIDLex OPIZ
301
288
263
274
cayugensis WIEGAND
cespitosus NOLTE ex RCHB.
chakassiensis KASCHINA
chamissoi A. BENN.
champlainii A. BENN.
280
A. BENN.
cheesemanii
294
307
273, 274
270
253, 257, 259, 260, 282, 283,
284
chongyangensisW.X. WANG
290
claytonii TUCK.
clystocarpus FERNALD
cognatus AsCH. et GRAEBN.
coloratus
HORNEM.
280
293, 294
278, 280
254, 257, 258, 277, 293
columbianus SUKSDORF
complanatus WILLD.
compressus
L.
306
288
250, 251, 288, 289-291
condylocarpus TAUSCH
confervoides
297
251, 300
RCHB.
conjungens HAGSTR.
connecticutensis J.W. ROBBINS
cooperi FRYER
cordatolanceolatus MERT. et W.D.J. KOCH
ex FIEBER
coriaceus FRYER
coriaceus MERT. et W.D.J. KOCH
corniculatus G. MEY.
cornutus
J. PRESL et C. PRESL
L.
278, 285
277
275
274
279
274
crassifolius FRYER
crenulatus D. DON
crispatus WALLMAN ex FR.
crispus
301
272
266
284
284
243, 248, 250, 264, 275, 278, 280, 284, 285,
291,298
cristatus
REGEL et MAACK
distinctus A. BENN. 242, 243, 255, 257, 259, 267, 268,
269, 271
243, 250, 301, 302
diversifoliusRAF.
270
drucei FRYER
253, 282, 283
drummondiiBENTH.
306
drupaceus0. LANG
292
dualis HAGSTR.
267
dubiusTIsELIus
272, 273
dunicolaTUR
291
elongatusWAHLENB.
252, 280, 281, 282
epihydrusRAF.
298
ethiopicusLYE
292
exiguusHAGSTR.
276
falcatus FRYER
277
fallax AsCH. et GRAEBN.
304
fasciculatus WOLFG.
289, 291
fauriei A. BENN.
245, 270, 272
faxonii MORONG
303, 305
fennicus HAGSTR.
254, 262, 270
ferrugineus HAGSTR.
295
fibrillosus FERNALD
264
fibrosus HAGSTR.
249, 303, 304, 305, 307
fihiformisPERS.
277
fischeri ASCH. et GRAEBN.
306
flabellatus BAB.
279
flexuosus WREDOW
266, 267
floridanus SMALL
267
fluitans auct.
266, 267, 274, 289
fluitans ROTH
306
fluviatilis SCHUBL. et G. MARTENS
243, 251, 295, 296
foliosus RAF.
268
fontigenus Y.H. Guo et al.
272
fragillimus HAGSTR.
268
franchetii A. BENN. et BAAGOE ex A. BENN.
friesii
251, 285, 288, 291, 292
RuPR.
curtisii MORONG
295
frondosus HAGSTR.
fryeri A. BENN.
curvatus
272
furcatus
277
gaudichaudii CHAM. et SCHLTDL.
287
gayi A. BENN.
243. 252, 299
A. BENN.
curvifolius HARTM.
cuspidatus
SCHRAD. ex MERT. et W.D.J.
cymatodes ASCH. et GRAEBN.
cymbifolius G. FIsCH.
cyprifolius LOWE ex GRAEBN.
danicus GAND.
decipiens NOLTE ex W.D.J. KOCH
delavayi A. BENN.
deminutus HAGSTR.
dentatus HAGSTR.
denticulatus LINK
dichotomus WALLR.
KOCH
HAGSTR.
gemmifer
275
gemmiparus J.W. ROBBINS
genuinus IELAK.
genuinus FERNALD
genuinus RCHB.
270
gessnacensis
RCHB.
G. FISCH.
292
306
gracilis A. BENN. ex GRAEBN.
gracilis FR.
gracilis KuzMIN et SKVORTZOV
gracilis WOLFG.
diffusus A. BENN.
diffusus HAGSTR.
297
gramineus
digynus WALLICH
dimidius CREP.
dimorphoides HAGSTR.
dimorphus RAF.
dissimilis A. BENN.
distachyus BELLARDI
268
272, 277
274
L.
301
301
307
276
292, 294
292
295
284
256, 266
272
292
306
276
243, 253, 256, 258, 264, 267, 272, 274,
275, 277, 278, 286
306
291
274
284
279
256
250, 287
251, 294
279
297
283
254, 255, 260, 261
graminifolius FR.
griffithii A. BENN.
grisebachii HEUFF.
groenlandicus HAGSTR.
grovesii DANDY et G. TAYLOR
harzii G. FISCH.
276
264, 280
292
293, 294
293, 298
266
Taxonomy of Potamogeton
313
harzii G. FISCH.ex GRAEBN.
haynesii HELLQ.et G.E. CROW
289,
heidenreichii ASCH. et GRAEBN.
helodes DUMoRT.
helveticus G. FISCH.
henningii A. BENN.
287,
henryi FERNALD
heterophyllus FR. (underP gramineus)
heterophyllus FR. (underP. lucens)
heterophyllus G. MEY.
heterophyllus SCHREB.
hibernicus A. BENN.
hibernicus HAGSTR.
hillii MORONG
251, 289,
hindostanicus HAGSTR.
hoggarensis DANDY
293,
hohenackeri GAND.
homophyllus HAGSTR.(underP. amplifolius)
homophyllus HAGSTR.(underP illinoensis)
hornemanoniiG. MEY.
hubeienisis W.X. WANG et al.
huillensis WELW.ex SCHINZ
hungaricus GAND.
hybridus PETAGNA
illinoensis MORONG
243,253,254,262,267,270,
inbaensis KADONO
indicus MIQ.
indicus ROXB.
insulanus HAGSTR.
interior RYDB.
intermixtus A. BENN.
interruptus KIT.
intortusifolius J.B. HE et al.
intramongolicus Y.C. MA
inivolutus FRYER
iriomotensis MASAMUNE
japonicus A. BENN.
japonicus FRANCH. et SAV.
javanicus HASSKARL
jeholensis KITAGAWA
johannis HESL.-HARR.
juncifolius A. KERN. ex C. FRITSCH
juzepczukii P. DOROF.et TZVELEV
kamogawaensis MIKI
kirkii SYME
kirkii SYMEex HOOK.f.
kochii F.W. SCHULTZ
kochii 0. LANG
kupfferi A. BENN.
kyushuensis KADONOet WIEGLEB
lactucaceus MONTANDON
lacunatus HAGSTR.
lacustris PEARSALL et PEARSALLf.
lacustris WALLMAN
lanceolatifolius TISELIUS
lanceolatus J.W. ROBBINS
lanceolatus POIR.
258, 293
266
295
275
257
306
288
291
276
275
lanceolatus SM.
lanciformis ROEM. et SCHULT.
latifolius
J.W. ROBBINS
307
latifolius
MORONG
299
276
latifolius
SLOBODA
276
275
latior HOLUB
258
266
leptocephalus
296
271
294
leschenaultii CHAM. et SCHLTDL.
lateralis
276
299
MORONG
laticaulis
WAHLENB.
288
latifolius
FIEBER
297
306
291
latifolius G. MEY. (under P pectinatus)
latifolius G. MEY. (under P pusillus)
307
279, 286
KOIDZ.
284
GAND.
leptophyllus
269
298
HAGSTR.
ligulatus
limosellifolius
284
262
272
linguatus
257
livingstonei
298
298
284
loculosus
loeselii
275
longifolius
MAXIM.
298
ex KORSH.
254, 261, 270, 273
HAGSTR.
285, 291
lintonii FRYER
liocarpus
297
ASCH.
306
A. BENN.
293
HAGSTR.
277
et SCHULT.
ROEM.
lonchites
276
TUCK.
274
J. GAY
longiligulatus FERNALD
272,273,277
274
268
269
270
304
278
295
268
A. CAMUS
243, 247, 248, 254, 264, 266, 267, 271, 273,
longipetiolatus
lucens L.
274, 275, 277, 278, 285
lundii K. RICHT.
277
A. BENN.
maackianus
243, 249, 271, 277, 279, 285,
286, 291
295
macellus
FERNALD
306
macounii
MORONG
271
macrocarpus
306
macrophylloides
277
299
285
270
298
271
264
macrophyllus
WALLR.
274
macrophyllus
WOLFG.
274
304
ex MACOUN
306
DOBROCHOT.
272
HAGSTR.
284
GAND.
macrorrhynchus
264
A. BENN.
macvicarii
304
HAGSTR.
magellanicus
major A. BENN. ex GRAEBN.
298
major FIEBER
287
304
277-279
major FR.
291
major MERT. et W.D.J. KOCH
292
291,299
267
267
256
malaianus auct.
271
276
275
286,291
malaianus
269, 271
MIQ.
malainoides
269
MIKI
manchuriensisA. BENN. (under P acutifolius)
251,
289, 290
mandschuriensis A. BENN. (under P perfoliatus)
marianensis
269
CHAM. et SCHLTDL.
269
284
292
293
279
256,277
methyensis
A. BENN.
279
mexicanus
A. BENN.
276
microcarpus Boiss. et REUT.
marinus
306
L.
mascarensis
maximus
278
CHAM. et SCHLTDL.
MORONG ex A. BENN.
membranaceus
HAGSTR.
276
258
272
269
256
G. Wiegleb & Z. Kaplan
314
microstachys WOLFG.
miduhikimo MAKINO
miguelensis DANDY
millardii HESL.-HARR.
minor BIv.
minor FIEBER
minor HOOK.
miyakezimensis HONDA
mongolicus A. BENN.
mongolicus MAXIM. ex A. BENN.
moniliformis H. ST. JOHN
monoginus MIKI
monogynus J. GAY
montanensis GAND.
montanus C. PRESL
montevidensis A. BENN.
monticolus
263
298
257
293
292
287
289
271
306
276
302
288
297
263
261
252, 281, 282
SCHWEIN. ex A. BENN.
ochreatus RAOUL
octandrus POIR.
250, 287
243, 252, 267, 291, 293, 298, 299,
300
291
oederi G. MEY.
ogdenii HELLQ. et R.. HILTON
245, 289, 296
266
olivaceus
BAAGOE
olivaceus
BAAGOE ex G. FISCH.
264, 285
olivaceus 0. LANG
275
HAGSTR.
291, 293
orientalis
297
orthorrhynchus GAND.
ovalifolius FIEBER
266
MERT. et W.D.J. KOCH ex FIEBER
ovalifolius
ovatifolius WALLR.
269, 270
CHAM. et SCHLTDL.
owaihiensis
277
277
pallidior GAND.
250, 286, 289, 290, 291, 293, 299
284
DRUCE
263
oxyphyllus
MIQ.
300
palmerii
266
paludosus
BOENN. ex STEUD.
266
mucronatus C. PREESL
mucronatus FIEBER
270
paludosus
BORY ex CHAM. et SCHLTDL.
256
292
pamiricus
BAAGOE
mucronatus
SCHRAD. ex RCHB.
291
panormitanus
mucronatus
SCHRAD. ex ROEM. et SCHULT.
morongii
A. BENN.
291
papuanicus
mucronatus SCHRAD. ex SONDER
291
paramoanus
muelleri
305
292
Biv.
244, 253, 268
WIEGLEB
281
R.R. HAYNES et HOLM-NIELS.
244, 255, 257, 265
HAGSTR.
A. BENN.
278
parmatus
multidenticulatus MORONG
301
parvifolius
BUCHENAU
298
muricatus
259
pauciflorus
PURSH
295
276
paucifolius OPIZ
HAGSTR.
myriophyllus
mysticus
J.W. ROBBINS
279, 293
MORONG
nakamurai YAMAUCHI et MOMIY.
natans
L.
242-244,
270,
nericius
HAGSTR.
264, 277
nerviger
WOLFG.
264, 274
WOLFG.
niagarensis TUCK.
nigrescens FR.
nipponicus MAKINO
nitens WEBER
nodosus
243, 255, 259, 265-268,
noltei G. FISCH.
nomotoensis
notarisii
GAND.
oakesianus
J.W. ROBBINS
VIv.
oblongus
obrutus A.W.
obscurus
WOOD
obtusus
peruvianus
277
perversus
MERT.
et W.D.J.
297
258
C. PRESL ex A. BENN.
269
268
A. BENN.
petiolaris C. PRESL
269
269
WOLFG.
petiolatus
297
274
phialae
307
philippinensis A. BENN.
planifolius G. MEY.
DUCROS ex ROEM. et SCHULT.
plantagineus
pleiophyllus HAGSTR.
POST
284
polygonifolius
270
298
polygonus
280
porrectifolius
porsildiorus
256
porteri
256
praelongus
PouRR.
A. BENN. ex GRAEBN.
KOCH
251, 296, 297
SCHLTDL.
occidentalis J.W. ROBBINS
occidentalis SIEBER ex CHAM. et SCHLTDL.
257
267
250, 286, 293
272
290
FERNALD
296
FERNALD
248, 252, 264, 275, 278, 279,
280, 285
prolixus W.D.J. KOCH
promontoricus HAGSTR.
protensus
WALLR.
304
prussicus HAGSTR.
pseudofluitans SYME
269
pseudofriesii
296
284
283
HAGSTR.
WULFEN
286
255, 256, 257, 264, 266, 277,
293
CHAM. et SCHLTDL.
porrigens
282
284
280
277, 278-280,
292
263
obtusifolius FIEBER
275,
HAGSTR. ex DRUCE
263
DC.
obtusifolius
273,
285, 286, 293
276
243, 252, 267, 268
oblongifolius KIRK ex HOOK. f.
oblongorufescens F.W. SCHULTZ
253, 264, 271,
perpygmaeus
244, 245, 267,
novaeboracensis MORONG
numasakianus A. BENN.
nuttallii CHAM. et SCHLTDL.
L.
perfoliatus
295
266
KADONO et T. NOGUCHI
WILLD. ex CHAM. et SCHLTDL.
pennsylvanicus
perneglectus GAND.
269, 270-272,
noltei A. BENN.
272
pedersenii TUR
264
245, 277, 278
POIR.
306-308
279
248, 252, 256, 265, 266-268,
274, 277, 293, 299, 307
nervigerus
276
242, 244, 248, 249, 267, 303, 305,
L.
pectinatus
DANDY et G. TAYLOR
266
273
306
264, 278
256
288, 292
315
Taxonomy of Potamogeton
pseudolucensHAGSTR.
pseudopolygonusHAGSTR.
pseudorutilusA. BENN.
pseudoziziiHAGSTR.
pulchelliformisHAGSTR.
pulcher TucK.
pumilusNUTT. ex A. BENN.
272
286
295
273
272
254, 260
285
pumilus WOLFG.
punense GALAN-MERA
purpurascens SEIDL ex J. PRESL et C. PRESL
pusilliformis HAGSTR.
L.
pusiUus
HAGSTR.
263
292
solomonensis
264
243, 253, 279
GILLOT
257, 293
robbinsii
OAKES
243, 249, 285
rostratus
HAGSTR.
A.
304, 305
rutiloides
rutilus
BENN.
sachalinensis
266
269
270
278
278
278
277
269
284
284
263
256
295
251, 294, 295
H. LEv.
277, 278
salicifolius auct.
salicifolius
272
270
FERNALD
WOLFG.
WOLFG.
275
274, 275, 278
salignus FRYER
samarifornis HAGSTR.
282, 283
sarmaticus
276, 277
275
MEMErS
scheelei G. PREuss ex GRAEBN.
schreberi G. FISCH.
schweinfurthii
A. BENN.
256
266, 270
254, 265, 273, 274, 278
sclerocarpus K. SCHUM.
scoliophyllus HAGSTR.
scoparius WALLR.
seemenii ASCH. et GRAEBN.
semicoloratus A. BENN.
semipellucidus W.D.J. KOCHet ZIz
serotinus SCHRAD. ex SCHULT. et SCHULT. f.
serrulatus OPIZ
serrulatus REGEL et MAACK
293
252, 254, 255, 270, 283, 284
spirillus
249, 303, 304
273
rugelii
274
266
298
rosulatus HAGSTR.
rothii A. BENN. ex G. FIsCH.
rothii G. FISCH.
rotundatus HAGSTR.
rotundifoliusMERT.et W.D.J. KOCHex FIEBER
rotundifolius MERT.et W.D.J. KOCHex RCHB.
rotundifolius SONDER
rotundifolius WALLR.
roxburghianus SCHULT. et SCHULT. f.
rubricans GAND.
rubrinaevus GAND.
rufescens SCHRAD. ex CHAM.
rufescentinatans F.W. SCHULTZ
WIEGLEB
282, 283
280
279
repens HAGSTR.
rivularis
siculus
sparganiifolius LAEST. ex FR.
spathulaeformis J.W. ROBBINS
spathulatus SCHRAD. ex W.D.J. KOCH et ZIz
spicatus ENGELM.
spirilliformis HAGSTR.
301
A. BENN.
304
251, 290
306
304
richardii SOLMS
A. BENN.
257
reniacoensis SPARRE
richardsonu
SCHUMACH.
260
283
J. PRESL
242, 243, 248, 251, 257, 258, 267, 279,
286, 288, 291, 292, 293-299
recurvatus
setaceus
sibiricus
284
siculus TINEO ex Guss.
similis A. BENN.
sinicus MIGO
skvortsovii KLINKOVA
280
pygmeus GALINIS
quinquenervius HAGSTR.
ramosus PECK
raunkiaeri G. FISCH.
serrulatus SCHRAD. ex RCHB.
sessilifolius A. CAMUS
sessilifolius HAGSTR.
281
262
306
276
275
267
249, 307, 308
251, 289, 295
A. BENN.
A. BENN.
tepperi
tepperiauct.
284
thomasii A. BENN.
A. BENN.
thunbergii
CHAM. et SCHLTDL.
263
268
258
298
293
277
261
249, 303
267
260
290
292
288, 289, 293
305, 307
254, 259, 260, 270, 283
sumatranus MIQ.
syriacus CHAM. et SCHLTDL.
tasmanicus HAGSTR.
tataricus LESSING
teganumensis MAKINO
tennesseensis FERNALD
tenuicaulis F. MUELL.
tenuifolius F. PHIL.
tenuifolius KUNTH
tenuifolius RAF.
tenuinervis A. CAMUS
tenuior MIQ.
tenuis WAHLENB.
tenuissimus MERT. et W.D.J. KOCH
266
304, 305
255, 257, 259, 283
HAGSTR.
270
263
285, 286
270
244, 255, 257, 263
subobtusus HAGSTR.
subretusus HAGSTR.
subrufus HAGSTR.
subsessilifolius A. CAMUS
subsibiricus HAGSTR.
subtrichoides SCHUR
sudermanicus HAGSTR.
suecicus K. RICHT.
sukcatus
301
301, 302
262
strictus PHIL.
stylatus HAGSTR.
subcordatus A. CAMUS
subflavus H. LORET et BARRANDON
subfuscus A. BENN.
subjavanicus HAGSTR.
subnitens HAGSTR.
suboblongus
272
256, 264
243, 250, 300
TUCK.
spoliatus HAGSTR.
stagnorus HAGSTR.
stenostachys K. ScHuM.
steriliformis HAGSTR.
sterilis HAGSTR.
striatus RuIz et PAV.
strictifolius
267, 277
270, 271
269
283
296
274
280
298
292
306
263
286
268
296
292
254, 255, 259, 270
259
263
243, 255, 264, 265
G. Wiegleb & Z. Kaplan
316
tiselii K. RICHT.
tonkinensis A. CAMUS
torquatus KoIDZ.
267
271
260
torssanderi
TISELIUS
275
tretocarpus
MAXIM. ex A. BENN.
271
tricarinatus auct.
260, 283
tricarinatus
F. MUELL. et A. BENN. (1892)
282
tricarinatus
F. MUELL. ex A. BENN. (1887)
259
CHAM. et SCHLTDL.
trichoides
242, 251, 285, 293,
297, 298
trichophyllus
MORONG
302
WALLR. ex GRAEBN.
tricostatus
301
trimmeri CASP.
297
trinervius
292
G. FISCH.
et Guss.
tuberculatus
TEN.
tuberculosus
RCHB.
297
297
tuberosus
ROXB.
284
tubulatus
HAGSTR.
293
J.W. ROBBINS
300
turionifer HAGSTR.
typicus FERNALD (underP epihydrus)
tuckermanii
292
typicus FERNALD(underP strictifolius)
280
295
typicus OGDEN
277
ulei K. SCHUM.
undulatus
upsaliensis
WOLFG.
252, 281, 282, 286
280, 285
TISELIUS
275
Specific and infraspecific names in other genera
Hydrogeton heterophyllus LOUR.
Spirillus tuckermanni J. GAY ex A. BENN.
Zannichellia cochlosperma A. BRAUNex A. BENN.
Zannichellia palustris var.gyrocarpa TRIMEN
298
300
300
300
292
uruguayensis A. BENN. et GRAEBN.
245, 273, 274, 278
vaginans BOJER ex A. BENN.
249, 302, 303-305, 307
vaginatus TURCZ.
306
vaillantii ROEM. et SCHULT.
276
varians MORONG ex FRYER
267, 293
variifolius THORE
243, 252, 299, 300
vaseyi J.W. ROBBINS
273
venosus A. BENN.
264
venustus BAAGOE
264
venustus BAAGOE ex A. BENN.
264
venustus BAAGOE ex HAGSTR.
274
volhynicus BESSER ex ROEM. et SCHULT.
275
vollmannii G. FISCH.
266
vulgaris CELAK.
265
vulgaris SCHUBL. et G. MARTENS
276
wolfgangii KIHLM.
242, 243, 253, 269, 270, 271, 274,
wrightiiMORONG
278, 286
275
xinganensis Y.C. MA
267, 299
yamagataensis KADONOet WIEGLEB
274
ZiZiiMERT.et W.D.J. KOCH
275
zizii W.D.J. KOCHex ROTH
306
zosteraceus FR.
288
zosterifolius SCHUMACH.
251, 289, 295, 296
zosteriformis FERNALD
288
zosterophyllusDUMORT.