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Vascular Plants of California
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Potamogeton gramineus
GRASS-LEAVED PONDWEED


Higher Taxonomy
Family: PotamogetonaceaeView Description 
Common Name: PONDWEED FAMILY
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 Description 


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.
Unabridged Reference: Haynes 1974 Rhodora 76:564--649; Haynes 1985 Sida 11:173--188; Wiegleb 1988 Fedde Rep Sp Nov Regni Veg 99:249--266; Wiegleb & Kaplan 1998, Folia Geobot 33: 241--316.
Potamogeton gramineus L.
NATIVE
Habit: Perennial herb, rhizomes matted. Stem: < 100 cm, branches generally many, short, cylindric. Leaf: submersed blade 2--10 cm, (3)10--27 mm wide, elliptic, minutely serrate, tip acute or long-tapered, veins 3--9, petiole 0 (<= 3 cm); floating generally on short, axillary branches, blade < petiole, 1.5--7 cm, 1--3 cm wide, elliptic to ovate, tip +- obtuse, veins 11--13; stipules < 3 cm, free, persistent. Inflorescence: 1--4 cm. Fruit: 1.9--2.3 mm, keels 3, beak erect, 0.3--0.5 mm. Chromosomes: n=26.
Ecology: Uncommon. Shallow water, ponds, lakes, bogs; Elevation: 900--2750 m. Bioregional Distribution: KR, NCoRI, CaRH, SNH, SnFrB, SnBr, GB; Distribution Outside California: to Alaska, Greenland, Arizona; Eurasia. Flowering Time: Jul--Aug Note: Hybridizes with Potamogeton alpinus, Potamogeton illinoensis, Potamogeton natans, Potamogeton nodosus, Potamogeton richardsonii.
Jepson eFlora Author: C. Barre Hellquist, Robert F. Thorne & Robert R. Haynes
Unabridged Reference: Haynes 1974 Rhodora 76:564--649; Haynes 1985 Sida 11:173--188; Wiegleb 1988 Fedde Rep Sp Nov Regni Veg 99:249--266; Wiegleb & Kaplan 1998, Folia Geobot 33: 241--316.
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Botanical illustration including Potamogeton gramineus

botanical illustration including Potamogeton gramineus

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Citation for this treatment: C. Barre Hellquist, Robert F. Thorne & Robert R. Haynes 2012, Potamogeton gramineus, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=39574, accessed on July 18, 2019.

Citation for the whole project: Jepson Flora Project (eds.) 2019, Jepson eFlora, http://ucjeps.berkeley.edu/eflora/, accessed on July 18, 2019.

No expert verified images found for Potamogeton gramineus.



Geographic subdivisions for Potamogeton gramineus:
KR, NCoRI, CaRH, SNH, SnFrB, SnBr, GB
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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).





 

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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time.