Search Field Guide
Advanced Search
MT Gov Logo
Montana Field Guide

Montana Field Guides

Grassy Pondweed - Potamogeton gramineus

Native Species

Global Rank: G5
State Rank: S4

Agency Status
MNPS Threat Rank:
C-value: 6

External Links

General Description
Stems terete, branched. Submersed leaves linear to linear-lanceolate, 2–10 cm × 3–15 mm; stipules 1–3 cm long, not sheathing. Floating leaves long-petiolate; blades elliptic, 2–7 cm long. Spikes 15–40 mm long, continuous. Tepals green, ca. 2 mm long. Fruits 2–3 mm long, keeled with a short, curved beak (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Diagnostic Characteristics
Stem terete or slightly flattened, not black spotted. Many submersed leaves more than 4 mm wide, 3-8 cm long, with 3-9 veins, sessile, not cordate or auriculate at the base. Stipular sheath 1-3 cm long. Beak of the achene less than 1.5 mm long and lacking a basal appendage. Plants not red tinged.

Species Range
Montana Range


Range Comments
Circumboreal south to most of U.S. (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 1309

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Shallow or deep, sometimes alkaline water of ponds, lakes; plains, valleys, montane (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Britton, N. L. and A. B. Brown. 1913. An Illustrated Flora of the Northern United States, Canada, and the British Possessions. 2nd Edition in 3 Volumes. New York, NY: Charles Scribner's Sons. B13BRI01PAUS.
    • Fassett, Norman C. 1940. A Manual of Aquatic Plants, 1st ed. New York: McGraw-Hill. B57FAS01PAUS.
    • Fernald, M. L. 1950. Gray's manual of botany. Eighth edition. A handbook of the flowering plants and ferns of the central and northeastern United States and Adjacent Canada. American Book Co., New York.
    • Garrett, P.A. 1983. Relationships between benthic communities, land use, chemical dynamics, and trophic state in Georgetown Lake. Ph.D. Dissertation. Bozeman, MT: Montana State University. 136 p.
    • Gleason, H. A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. New York Botanical Garden, Bronx, NY. 910 pp.
    • Horpestad, A.A. 1969. Factors affecting the distribution and abundance of aquatic macrophytes in parts of the Madison, Firehole and Gibbon Rivers. M.Sc. Thesis. Bozeman, MT: Montana State University. 88 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Linnaeus, C. 1753. Species Plantarum. A fascimile of the first edition printed by Adlard & Son, Bartholomew Press, Dorking, Great Britain. 2 vol.
  • Web Search Engines for Articles on "Grassy Pondweed"
Login Logout
Citation for data on this website:
Grassy Pondweed — Potamogeton gramineus.  Montana Field Guide.  .  Retrieved on , from