Potamogeton richardsonii
Richardson's pondweed
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Family: Potamogetonaceae · Type: Herb · Native
Potamogeton richardsonii (Richardson's pondweed) is a native California herb in the Potamogetonaceae family, recognized by crinkly leaf margins, clasping heart-shaped bases, and flat (not hooded) tips distinctive.
Richardson's pondweed is a native perennial found in coastal, Klamath, Cascade Range, central Sierra Nevada, and northern Sierra Nevada regions in shallow to deep water habitats including ponds, lakes, and streams at elevations up to 2,800 meters. Flowering from July to August, this aquatic plant produces small, inconspicuous flowers on compact inflorescences less than 4 centimeters long. Growing with matted rhizomes and slender stems up to 70 centimeters long, it develops branches that are generally straight and cylindrical. Its submersed leaves are distinctive, linear to lance-ovate, 1 to 12 centimeters long with widths of 10 to 20 millimeters, featuring crinkly margins near the tip and a clasping base. The plant's leaves have 3 to 35 visible veins and persistent stipules that remain as delicate fibers after drying.
Identification and appearance
Key characters: 16 sympatric species; crinkly leaf margins, clasping heart-shaped bases, and flat (not hooded) tips distinctive
Habitat and range
Habitat: Uncommon. Shallow to deep water, ponds, lakes, lagoons, streams
Elevation: < 2800 m
Outside California: to Alaska, Colorado, eastern North America
Bloom period
Potamogeton richardsonii blooms Jul-Aug.
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 richardsonii native to California?
Yes. Potamogeton richardsonii is native to California (recorded as native).
When does Potamogeton richardsonii bloom?
Potamogeton richardsonii blooms Jul-Aug.
What plant family does Potamogeton richardsonii belong to?
Potamogeton richardsonii is in the Potamogetonaceae family, genus Potamogeton.
What habitat does Potamogeton richardsonii grow in?
Potamogeton richardsonii grows in Uncommon. Shallow to deep water, ponds, lakes, lagoons, 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.