Eleocharis tenuis var. tenuis
Slender spikerush
(c) Nathan Aaron, some rights reserved (CC BY), uploaded by Nathan Aaron · licence
Family: Cyperaceae · Type: Grass · Not Native
Eleocharis tenuis var. tenuis (Slender spikerush) is a non-native California grass in the Cyperaceae family, recognized by non-native status, extremely thin 4-5-angled stems, and net-patterned fruits.
Slender spikerush is a naturalized perennial herb found in the northern Coast Ranges in pond habitats at elevations of 10 to 1,100 meters. Flowering in July, this plant produces green to yellow-green flowers in small spikelets 3 to 6 millimeters long. Growing with thin cylindric or slightly angled stems 5 to 90 centimeters tall, it has a tough rhizome less than one millimeter in diameter. Its leaf sheaths are firm and persistent, with obtuse to acute tips that sometimes feature a small tooth. The fruit is tiny, about 0.6 to 0.9 millimeters long, with a fine wrinkled surface and occasionally accompanied by 1 to 3 perianth bristles.
Identification and appearance
Key characters: 13 sympatric species; key features are non-native status, extremely thin 4-5-angled stems, and net-patterned fruits
Habitat and range
Habitat: Ponds
Elevation: 10-1100 m
Outside California: Nova Scotia to South Carolina, Louisiana, naturalized in Germany
Bloom period
Eleocharis tenuis var. tenuis blooms Jul.
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 tenuis var. tenuis native to California?
No. Eleocharis tenuis var. tenuis is not native to California (recorded as not native).
When does Eleocharis tenuis var. tenuis bloom?
Eleocharis tenuis var. tenuis blooms Jul.
What plant family does Eleocharis tenuis var. tenuis belong to?
Eleocharis tenuis var. tenuis is in the Cyperaceae family, genus Eleocharis.
What habitat does Eleocharis tenuis var. tenuis grow in?
Eleocharis tenuis var. tenuis grows in Ponds.
Related species
Other California species in the same genus, family, or bioregion.
- Eleocharis torticulmis — California twisted spikerush
- Eleocharis acicularis — Needle spikerush
- Eleocharis acicularis var. acicularis — Needle spike rush
- Eleocharis acicularis var. gracilescens — Needle spike rush
- Eleocharis acicularis var. occidentalis — Needle spike rush
- Eleocharis atropurpurea — Purple spikerush
- Eriophorum gracile — Slender cottongrass
- Eriophorum sp. — Cotton grass
- Fimbristylis autumnalis — Slender fimbry
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.