Fimbristylis autumnalis
Slender fimbry
(c) Jay Horn, some rights reserved (CC BY), uploaded by Jay Horn · licence
Family: Cyperaceae · Type: Grass · Not Native
Fimbristylis autumnalis (Slender fimbry) is a non-native California grass in the Cyperaceae family.
Slender fimbry is a naturalized annual found in the Sacramento Valley in damp open disturbed places, especially along streams, at elevations below 100 meters. Flowering from July to September, this plant produces small, delicate spikelets up to 7 millimeters long with inconspicuous flowers. Growing with slender stems less than 1 millimeter in diameter and reaching 20 to 30 centimeters tall, it forms compact clusters in moist environments. Its narrow leaf blades are less than 2 millimeters wide, with scabrous margins and short-ciliate sheath edges. The fruit is a tiny, pale brown, thick three-sided structure less than 1 millimeter long with prominent angles.
Identification and appearance
Key characters: 0 sympatric species; geographically isolated in ScV
Habitat and range
Habitat: Damp open disturbed places, especially along streams
Elevation: < 100 m
Outside California: eastern North America
Bloom period
Fimbristylis autumnalis blooms Jul-Sep.
How to tell it apart
vs Juncus: Fimbristylis has triangular stems and scabrous sheath edges; Juncus has round stems and smooth sheaths.; vs Bulbostylis: Fimbristylis has short sandpaper-like hairs on sheaths; Bulbostylis has long, soft, conspicuous fringe.; vs Bolboschoenus: Fimbristylis has scabrous sheath edges; Bolboschoenus has smooth sheaths and often has tubers.; vs Scirpus: Fimbristylis has distinctly rough, hairy sheath tips; Scirpus has smooth sheaths.; vs Calliscirpus: Fimbristylis has scabrous sheath tips; Calliscirpus has smooth sheaths and tufted growth.
Frequently asked questions
Is Fimbristylis autumnalis native to California?
No. Fimbristylis autumnalis is not native to California (recorded as not native).
When does Fimbristylis autumnalis bloom?
Fimbristylis autumnalis blooms Jul-Sep.
What plant family does Fimbristylis autumnalis belong to?
Fimbristylis autumnalis is in the Cyperaceae family, genus Fimbristylis.
What habitat does Fimbristylis autumnalis grow in?
Fimbristylis autumnalis grows in Damp open disturbed places, especially along 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.