Eleocharis atropurpurea
Purple spikerush
(c) Jay Horn, some rights reserved (CC BY), uploaded by Jay Horn · licence
Family: Cyperaceae · Type: Grass · Native
Eleocharis atropurpurea (Purple spikerush) is a native California grass in the Cyperaceae family, recognized by 20 co-occurring species; black fruits and annual habit.
Purple spikerush is a California native annual found in the Great Valley, southern California coastal areas, and San Bernardine Mountains in fresh wet bare soil at elevations below 800 meters. Flowering during summer and fall, this tiny plant produces dark purplish spikes in compact clusters less than 6 millimeters long. Growing as a delicate tufted annual just 2 to 12 centimeters tall with extremely thin stems less than 0.3 millimeters in diameter, it forms dense small clusters in wet soil. Its leaves are characterized by firm distal sheaths with acute tips, creating a compact and minimalist growth form. The fruit is small and distinctive, measuring just 0.3 to 0.5 millimeters wide, developing from black to brown with vestigial white perianth bristles.
Identification and appearance
Key characters: 20 co-occurring species; black fruits and annual habit are diagnostic
Habitat and range
Habitat: Very local. Fresh wet bare soil
Elevation: < 800 m
California counties: San Bernardino, Shasta, Fresno, Glenn, Butte, Yuba, Tehama
Outside California: to British Columbia, also New Mexico to Michigan, Florida
Bloom period
Eleocharis atropurpurea blooms Summer-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 atropurpurea native to California?
Yes. Eleocharis atropurpurea is native to California (recorded as native).
When does Eleocharis atropurpurea bloom?
Eleocharis atropurpurea blooms Summer-fall.
Where in California does Eleocharis atropurpurea grow?
Eleocharis atropurpurea occurs in San Bernardino, Shasta, Fresno, Glenn, Butte, Yuba, Tehama, at elevations of < 800 m.
What plant family does Eleocharis atropurpurea belong to?
Eleocharis atropurpurea is in the Cyperaceae family, genus Eleocharis.
What habitat does Eleocharis atropurpurea grow in?
Eleocharis atropurpurea grows in Very local. Fresh wet bare soil.
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.