Potamogeton pusillus
Small pondweed
(c) chiuluan, some rights reserved (CC BY), uploaded by chiuluan · licence
Family: Potamogetonaceae · Type: Herb · Native
Potamogeton pusillus (Small pondweed) is a native California herb in the Potamogetonaceae family, recognized by small size and fused stipules help distinguish from other narrow-leaved species.
Small pondweed is a California native perennial found in coastal, northern Sierra Nevada, Sierra Nevada, Central Valley, San Francisco Bay, southern Coastal Range, southwestern California, Great Basin, and Mojave Desert regions in shallow water, ponds, lakes, vernal pools, and slow streams at elevations below 2,700 meters. Flowering from May to June, this aquatic plant produces small, inconspicuous flowers arranged in interrupted whorls. Growing with slender stems up to one meter long and cylindrical in shape, it develops delicate winter buds at the stem tips. Its submersed leaves are thread-like to linear, typically one to three veined, and sessile with stipules fused below the midpoint. The fruit is small, less than 2.5 millimeters long, with concave sides and a symmetric tip.
Identification and appearance
Key characters: 15 sympatric species; small size and fused stipules help distinguish from other narrow-leaved species
Habitat and range
Habitat: Shallow water, ponds, lakes, vernal pools, slow streams
Elevation: < 2700 m
California counties: Riverside, San Diego, Marin, San Bernardino, Fresno, San Mateo, Inyo, Butte, Humboldt, Mono, Santa Clara, Merced, Lassen, Los Angeles, Kern, Sonoma, Modoc, Colusa, San Luis Obispo, Lake, Siskiyou, Yuba, Tulare, Sutter, Napa, Solano, Tehama, Alameda, Mendocino, Monterey, Plumas, Stanislaus, Santa Barbara, Tuolumne, Mariposa
Outside California: circumboreal
Bloom period
Potamogeton pusillus blooms May-Jun.
How to tell it apart
vs Persicaria: Potamogeton flowers float on water; Persicaria has terrestrial pink/white flower spikes above solid ground.; vs Stuckenia: Potamogeton flowers emerge above water on stiff stalks; Stuckenia flowers stay underwater on flexible stalks.; vs Alisma: Potamogeton has inconspicuous spike flowers; Alisma has showy white three-petaled flowers in branched clusters.; vs Ranunculus: Potamogeton has tiny greenish spike flowers; Ranunculus has bright yellow buttercup flowers with visible petals.; vs Myriophyllum: Potamogeton has broad or ribbon-like leaves; Myriophyllum has feathery, finely divided leaves like a bottlebrush.
Frequently asked questions
Is Potamogeton pusillus native to California?
Yes. Potamogeton pusillus is native to California (recorded as native).
When does Potamogeton pusillus bloom?
Potamogeton pusillus blooms May-Jun.
Where in California does Potamogeton pusillus grow?
Potamogeton pusillus occurs in Riverside, San Diego, Marin, San Bernardino, Fresno, San Mateo, Inyo, Butte and other counties, at elevations of < 2700 m.
What plant family does Potamogeton pusillus belong to?
Potamogeton pusillus is in the Potamogetonaceae family, genus Potamogeton.
What habitat does Potamogeton pusillus grow in?
Potamogeton pusillus grows in Shallow water, ponds, lakes, vernal pools, slow streams.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.