Cyperus bipartitus
Slender flatsedge
(c) Tom Norton, some rights reserved (CC BY) · licence
Family: Cyperaceae · Type: Grass · Native
Cyperus bipartitus (Slender flatsedge) is a native California grass in the Cyperaceae family, recognized by lateral vein absence and 2 stigmas are key.
Slender flatsedge is a California native annual found in northwestern California, central Sierra Nevada Foothills, and northern Sierra Nevada High in sandy habitats along pond shores and sandbars at elevations of 100 to 1,500 meters. Flowering from July to November, this delicate sedge produces small brown to red-brown flowers in compact, open ovoid spikes approximately 8 to 15 millimeters wide. Growing with slender stems 3 to 25 centimeters tall, it forms a sparse, delicate inflorescence with 0 to 4 short rays. Its flowers have 2 distinctive stigmas and produce tiny, finely pitted fruits 1 to 1.5 millimeters long. The plant's linear-oblong spikelets, arranged in clusters of 3 to 10, contribute to its distinctive appearance in wet, sandy environments.
Identification and appearance
Key characters: 8 sympatric species; lateral vein absence and 2 stigmas are key
Habitat and range
Habitat: Sandbars, pond shores
Elevation: 100-1500 m
California counties: Siskiyou, Calaveras, El Dorado, Humboldt, Sacramento, Trinity, Sonoma, Shasta, Butte, Tuolumne, San Joaquin, Sutter, Tehama, Yuba, Stanislaus, Santa Clara, Kern, Placer
Outside California: to Canada, South America
Bloom period
Cyperus bipartitus blooms Jul-Nov.
How to tell it apart
vs Carex: Cyperus has umbrella clusters with flat spikes; Carex has brown/green spikelets with seeds in individual flasks.; vs Scirpus: Cyperus has flattened ribbon-like spikes; Scirpus has rounded, cylindrical spikelets.; vs Juncus: Cyperus has triangular stems and flat flower spikes; Juncus has round stems and individual flowers.; vs Sticherus: Cyperus is a sedge with triangular stem; Sticherus is a fern with fronds.; vs Eleusine: Cyperus has triangular stems; Eleusine is a grass with round stems and obvious grass flowers.
Frequently asked questions
Is Cyperus bipartitus native to California?
Yes. Cyperus bipartitus is native to California (recorded as native).
When does Cyperus bipartitus bloom?
Cyperus bipartitus blooms Jul-Nov.
Where in California does Cyperus bipartitus grow?
Cyperus bipartitus occurs in Siskiyou, Calaveras, El Dorado, Humboldt, Sacramento, Trinity, Sonoma, Shasta and other counties, at elevations of 100-1500 m.
What plant family does Cyperus bipartitus belong to?
Cyperus bipartitus is in the Cyperaceae family, genus Cyperus.
What habitat does Cyperus bipartitus grow in?
Cyperus bipartitus grows in Sandbars, pond shores.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · 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.