Eleocharis obtusa
Blunt spike rush
(c) Douglas Goldman, some rights reserved (CC BY-SA), uploaded by Douglas Goldman · licence
Family: Cyperaceae · Type: Grass · Native
Eleocharis obtusa (Blunt spike rush) is a native California grass in the Cyperaceae family, recognized by 22 co-occurring species; flat wide tubercle.
Blunt spike rush is a California native annual found in northwestern California, the Sierra Nevada, northern Sierra Nevada foothills, and central coastal regions in fresh shores, marshes, seepages, and stream beds at elevations below 1,600 meters. Flowering from late spring to fall, this plant produces small, inconspicuous flowers in slender spikes 5 to 13 millimeters long. Growing in tufted clusters with thin cylindrical stems 3 to 50 centimeters tall, it forms dense, delicate patches in wet environments. Its leaf sheaths are firm and persistent, with an obtuse to acute tip featuring a subtle tooth-like projection less than 0.3 millimeters long. The fruit is small and smooth, with 5 to 7 delicate perianth bristles that typically extend beyond the flat, adherent tubercle.
Identification and appearance
Key characters: 22 co-occurring species; flat wide tubercle is diagnostic
Habitat and range
Habitat: Fresh shores, marshes, seepages, stream beds, disturbed places
Elevation: < 1600? m
California counties: Trinity, Humboldt, Marin, Siskiyou, Tuolumne, Los Angeles, Yuba, Butte, Plumas, Nevada, Sacramento, Sierra, Modoc, Mariposa, Lake, Shasta, San Benito, Placer, San Luis Obispo
Outside California: to southern British Columbia, Quebec, Florida, Hawaii
Bloom period
Eleocharis obtusa blooms Late spring-fall.
How to tell it apart
vs Carex: Eleocharis has single spikelet with no bracts below, Carex has leafy bracts and multiple spikes.; vs Isolepis: Eleocharis has no bracts below spikelet, Isolepis has conspicuous leaf-like bracts extending beyond flowers.; vs Schoenoplectus: Eleocharis has single terminal spikelet, Schoenoplectus has multiple spikelets in clusters.; vs Juncus: Eleocharis spikelets are flattened oval, Juncus flowers are round with visible petals in clusters.; vs Equisetum: Eleocharis has grass-like stems with flower spikelets, Equisetum has jointed hollow stems with cone-like structures.
Frequently asked questions
Is Eleocharis obtusa native to California?
Yes. Eleocharis obtusa is native to California (recorded as native).
When does Eleocharis obtusa bloom?
Eleocharis obtusa blooms Late spring-fall.
Where in California does Eleocharis obtusa grow?
Eleocharis obtusa occurs in Trinity, Humboldt, Marin, Siskiyou, Tuolumne, Los Angeles, Yuba, Butte and other counties, at elevations of < 1600? m.
What plant family does Eleocharis obtusa belong to?
Eleocharis obtusa is in the Cyperaceae family, genus Eleocharis.
What habitat does Eleocharis obtusa grow in?
Eleocharis obtusa grows in Fresh shores, marshes, seepages, stream beds, disturbed places.
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.