Potamogeton foliosus subsp. foliosus
Stems: glands rarely present, less than or equal to 0.3 mm diam. Leaves: stipules greenish to brown, delicate to slightly fibrous, veins decaying with age. Inflorescences: spikes continuous, rarely interrupted. Fruits olive-green to green-brown, 1.5–2.7 × 1.2–2.2 mm; keel greater than or equal to 0.2 mm high; beak 0.2–0.6 mm. 2n = 28.
Phenology: Flowering and fruiting spring–fall.
Habitat: Wide variety of waters of lakes and streams, either slow- or rapidly flowing
Elevation: 0–2300 m
Distribution
Alta., B.C., Man., N.B., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon, Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo., Mexico, West Indies, Central America (Guatemala, Costa Rica).
Discussion
Potamogeton foliosus subsp. foliosus is probably the most common linear-leaved species of the family in North America, and it is probably the easiest to determine. Any linear-leaved Potamogeton specimen with fruits having an undulating winglike abaxial keel most likely is this taxon.
Selected References
None.