Isolepis setacea
Bristleleaf bulrush
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Family: Cyperaceae · Type: Grass · Not Native
Isolepis setacea (Bristleleaf bulrush) is a non-native California grass in the Cyperaceae family, recognized by 2 leaves per stem and lengthwise-ribbed fruits.
Bristleleaf bulrush is a naturalized perennial herb found in northern California Coast and northern Sierra Nevada regions on stream and pond shores, generally in coastal areas at elevations below 1,500 meters. Flowering from late spring through fall, this plant produces small inconspicuous flowers in delicate clusters. Growing with thin rhizomatous stems 3 to 25 centimeters tall, it forms compact clumps in wet habitats. Its leaves are sparse, typically two per plant, with fine, bristle-like characteristics. The tiny fruit is ribbed lengthwise, approximately 1 millimeter long and slightly wider than tall.
Identification and appearance
Key characters: 3 sympatric species; key features are 2 leaves per stem and lengthwise-ribbed fruits
Habitat and range
Habitat: Stream, pond shores, generally coastal
Elevation: < 1500 m
California counties: Humboldt, Del Norte, Butte, Nevada, Placer, Mendocino, Yuba, Plumas, Sierra
Outside California: to British Columbia, Eurasia, Africa, Australia, New Zealand
Bloom period
Isolepis setacea blooms Late spring-fall.
How to tell it apart
vs Eleocharis: Isolepis has multiple parallel veins in its bracts; Eleocharis bracts have just a single midvein.; vs Juncus: Isolepis flowers grow in spikelets with overlapping scales; Juncus has separate flowers with 6 perianth parts.; vs Carex: Isolepis has bisexual flowers in open spikelets; Carex has separate male/female flowers in enclosed sacs.; vs Triglochin: Isolepis has scaly spikelets typical of sedges; Triglochin has spike-like flower clusters with capsules.; vs Lipocarpha: Isolepis has one bract per flower; Lipocarpha has two nested bracts (inner and outer) per flower.
Frequently asked questions
Is Isolepis setacea native to California?
No. Isolepis setacea is not native to California (recorded as not native).
When does Isolepis setacea bloom?
Isolepis setacea blooms Late spring-fall.
Where in California does Isolepis setacea grow?
Isolepis setacea occurs in Humboldt, Del Norte, Butte, Nevada, Placer, Mendocino, Yuba, Plumas and other counties, at elevations of < 1500 m.
What plant family does Isolepis setacea belong to?
Isolepis setacea is in the Cyperaceae family, genus Isolepis.
What habitat does Isolepis setacea grow in?
Isolepis setacea grows in Stream, pond shores, generally coastal.
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.