Potamogeton illinoensis

Shining pondweed, Shining Pondweed

Family: Potamogetonaceae · Type: perennial · Native

Shining pondweed is a California native perennial found in northern and central California regions including the Cascade Range, Sierra Nevada, Central Valley, Coast Ranges, and Great Basin, inhabiting lakes, ponds, and streams at elevations of 400 to 2,350 meters. Flowering from June to August, this aquatic plant produces small greenish flowers in slender underwater inflorescences less than 6 centimeters long. Growing with multiple branching stems up to 150 centimeters long, it spreads through rhizomes and develops both underwater and floating leaves. Its underwater leaves are elliptic to oblanceolate, 6 to 20 centimeters long with 7 to 19 fine veins, while floating leaves are wider and more rounded, with 13 to 29 veins. The plant produces small fruits 2.5 to 3.6 millimeters long with three distinct keels and a short erect beak.

Habitat: Lakes, ponds, streams

Bloom period: Jun-Aug

Elevation: 400-2350 m

Bioregions: NCoR, CaR, SNH, GV, CW (exc SCoRI), SnGb, SnBr, PR, GB

California counties: San Bernardino, Lake, Butte, Los Angeles, Sonoma, Siskiyou, San Francisco, Monterey, Mono, Mendocino, Modoc, Inyo, Alameda, San Mateo, San Diego, San Luis Obispo, Plumas, Santa Clara, Santa Cruz, Yuba, Lassen, Merced, San Joaquin, Stanislaus, Placer

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