Potamogeton gramineus

Grass-leaved pondweed

Family: Potamogetonaceae · Type: perennial · Native

Grass-leaved pondweed is a native perennial aquatic plant found in the Klamath Ranges, northern California coast ranges, high Cascade Range, Sierra Nevada, San Francisco Bay Area, and Great Basin in shallow water, ponds, lakes, and bogs at elevations of 900 to 2,750 meters. Flowering from July to August, this plant produces small underwater flowers on compact inflorescences 1 to 4 centimeters long. Growing with branching stems up to 100 centimeters long and matted rhizomes, it forms intricate underwater colonies with distinctive leaf types. Its underwater leaves are elliptic, 2 to 10 centimeters long and 10 to 27 millimeters wide, with 3 to 9 delicate veins, while floating leaves are shorter and broader with 11 to 13 veins. The fruit is small, approximately 2 millimeters long with three distinctive keels and a short erect beak.

Habitat: Uncommon. Shallow water, ponds, lakes, bogs

Bloom period: Jul-Aug

Elevation: 900-2750 m

Bioregions: KR, NCoRI, CaRH, SNH, SnFrB, SnBr, GB

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.