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Potamogeton foliosus subsp. foliosus

Higher Taxonomy
Family: PotamogetonaceaeView DescriptionDichotomous Key

Habit: Annual, perennial herb, aquatic, (generally fresh to alkaline), glabrous, from rhizomes, tubers, or winter buds. Stem: erect, simple to branched, cylindric to compressed, rooting at lower nodes; nodal glands present or not. Leaf: simple, cauline, alternate or in subopposite pairs; submersed thread-like to round, sessile or petioled; floating present or not, elliptic to ovate, petioled, leathery; sheath open, continuous with petiole or +- free from blade base, generally stipuled, stipules fused and ligule-like or not. Inflorescence: spike, cylindric to spheric, axillary or terminal, generally emergent, peduncled; bracts 0. Flower: inconspicuous, bisexual; perianth parts [0]4, clawed, +- green, limb generally adaxially concave; stamens [2]4, each fused to base of perianth part [or not], filament generally 0 [short, wide], anthers open to outside; pistils [1]4, ovary 1-chambered, ovule 1, attached to chamber base, style 0 or short. Fruit: drupe, generally obovate, sessile. Seed: 1.
Genera In Family: 3 genera, +- 95 species: worldwide. Note: Recently treated elsewhere to include Zannichelliaceae. Ruppia moved to Ruppiaceae.
eFlora Treatment Author: C. Barre Hellquist, Robert F. Thorne & Robert R. Haynes
Scientific Editor: Thomas J. Rosatti.
Genus: PotamogetonView DescriptionDichotomous Key

Common Name: PONDWEED
Habit: Annual, perennial herb, rhizomed or not, tubers 0, winter buds generally 0. Stem: simple or branched, cylindric to compressed; nodal glands present or 0. Leaf: submersed, also floating or not, generally flat, generally green, entire to finely serrate; submersed sessile or not, linear to round, tip rounded to acuminate, veins 1--35; floating 0 or generally petioled, elliptic to ovate, leathery; stipules of submersed leaves free from blade base or fused to it < 1/2 stipule length. Inflorescence: generally floating to emergent; peduncle stiff. Fruit: generally beaked, abaxially with 0 or 1 central keel, 0 or 2 lateral, sometimes lower keels, sides concave to convex.
Species In Genus: +- 88 species: generally temperate northern hemisphere. Etymology: (Greek: river neighbor, from aquatic habitat) Note: Other taxa in TJM (1993) moved to Stuckenia.
Species: Potamogeton foliosusView Description 

Habit: Annual (perennial herb), rhizomes rare, slender, winter buds present. Stem: branches many, +- compressed; nodal glands 0 (faint). Leaf: submersed, sessile, 1--10 cm, linear, veins 1--3(5); stipules fused, sheath-like. Inflorescence: 1.5--7 mm, short-cylindric to spheric; peduncle 0.3--1.1(3.7) cm, club-shaped. Fruit: olive to green-brown, keel 1, wavy, wing-like, sides convex to +- concave.

Potamogeton foliosus Raf. subsp. foliosus
Habit: Rhizomes slender, rare. Stem: < 100 cm, compressed; nodal glands faint or 0. Leaf: 1--10 cm, 0.3--2.5 mm wide, tip acute to abruptly pointed; stipules < 2 cm, veins in age decaying, occasionally persistent as delicate fibers. Inflorescence: +- spheric, generally not interrupted. Fruit: 1.5--2.7 mm, 1.2--2.2 mm wide, olive to green-brown, keel 0.2--0.4 mm high, beak 0.2--0.6 mm. Chromosomes: 2n=28.
Ecology: Common. Ponds, lakes, streams; Elevation: < 2300 m. Bioregional Distribution: NW, CaRH, SNF, n SNH, GV, CW, SW (exc ChI), GB, D; Distribution Outside California: to Alaska, eastern Canada, Central America. Flowering Time: Jul--Oct
Synonyms: Potamogeton foliosus var. foliosus
eFlora Treatment Author: C. Barre Hellquist, Robert F. Thorne & Robert R. Haynes
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botanical illustration including Potamogeton foliosus subsp. foliosus


Citation for this treatment: C. Barre Hellquist, Robert F. Thorne & Robert R. Haynes 2017. Potamogeton foliosus subsp. foliosus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on April 28, 2017.

Citation for the whole project: Jepson Flora Project (eds.) 2017. Jepson eFlora,, accessed on April 28, 2017.

Geographic subdivisions for Potamogeton foliosus subsp. foliosus:
NW, CaRH, SNF, n SNH, GV, CW, SW (exc ChI), GB, D;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.