Eleocharis pachycarpa
Black sand spikerush
Family: Cyperaceae · Type: Grass · Not Native
Eleocharis pachycarpa (Black sand spikerush) is a non-native California grass in the Cyperaceae family, recognized by 24 co-occurring species; sharp 4-angled stems and plantlet formation.
Black sand spikerush is a naturalized perennial herb found in northern California coastal areas, central Sierra Nevada foothills, Great Valley, and North Coast Ranges in fresh shorelines, ponds, and streambeds at elevations of 100 to 1,400 meters. Flowering from late spring to summer, this plant produces small spikelets 3 to 10 millimeters long in dense clusters. Growing in compact clumps with sharp four-angled stems 7 to 50 centimeters tall, it forms a tough, mostly hidden rhizome-like caudex. Its leaf sheaths are firm and persistent with acute tips, and the plant develops distinctive three-sided fruits less than 1.2 millimeters wide. The spikelets often form small plantlets, with 8 to 15 flower bracts and three-part stigmas.
Identification and appearance
Key characters: 24 co-occurring species; sharp 4-angled stems and plantlet formation are diagnostic
Habitat and range
Habitat: Local, uncommon. Fresh shores, ponds, streambeds, seeps, springs, fens
Elevation: 100-1400 m
California counties: Calaveras, Butte, Humboldt, Sacramento, Tuolumne, El Dorado, Nevada, Placer, Yuba, Marin, Modoc, Stanislaus, San Luis Obispo, Amador
Outside California: Nevada, native to Argentina, Chile
Bloom period
Eleocharis pachycarpa blooms Late spring-summer.
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 pachycarpa native to California?
No. Eleocharis pachycarpa is not native to California (recorded as not native).
When does Eleocharis pachycarpa bloom?
Eleocharis pachycarpa blooms Late spring-summer.
Where in California does Eleocharis pachycarpa grow?
Eleocharis pachycarpa occurs in Calaveras, Butte, Humboldt, Sacramento, Tuolumne, El Dorado, Nevada, Placer and other counties, at elevations of 100-1400 m.
What plant family does Eleocharis pachycarpa belong to?
Eleocharis pachycarpa is in the Cyperaceae family, genus Eleocharis.
What habitat does Eleocharis pachycarpa grow in?
Eleocharis pachycarpa grows in Local, uncommon. Fresh shores, ponds, streambeds, seeps, springs, fens.
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.