Schoenoplectus americanus
Olney's three-square bulrush, Olney's Three-Square Bulrush
Photo by Chez Brungraber
Family: Cyperaceae · Type: Grass · Native
Schoenoplectus americanus (Olney's three-square bulrush) is a native California grass in the Cyperaceae family, recognized by uniquely identified by sharp-3-sided stems with deep-concave sides.
Olney's three-square bulrush is a California native perennial found in the Klamath Ranges, northern coastal California, high Cascade Range, Central Valley, San Francisco Bay Area, southwestern California, Great Basin, and desert regions in mineral-rich or brackish marshes and shores at elevations below 2,200 meters. Flowering during summer, this plant produces small clustered spikelets 5 to 15 millimeters long with inconspicuous flowers. Growing 0.4 to 2.5 meters tall with a long rhizome, it features distinctively three-sided stems 3 to 10 millimeters in diameter with deep concave sides and sharp edges. Its leaves are 2 to 8 millimeters wide, three-sided toward the tip, and generally flat, emerging from sheaths that do not split. The fruit is small, smooth, and 1.8 to 2.8 millimeters long with two or three obscure sides.
Identification and appearance
Key characters: 9 sympatric species; uniquely identified by sharp-3-sided stems with deep-concave sides
Habitat and range
Habitat: Mineral-rich or brackish marshes, shores, fens, springs
Elevation: < 2200 m
California counties: San Bernardino, San Diego, Los Angeles, Riverside, Orange, Imperial, Inyo, Kern, Marin, Merced, Modoc, Mono, Monterey, Plumas, San Benito, San Luis Obispo, Santa Clara, Solano, Sonoma, Ventura, Alpine, Santa Barbara, Tulare, Napa, Fresno, Contra Costa, Colusa, Nevada, San Mateo, Siskiyou, Stanislaus, Humboldt, Del Norte, Mendocino, Yolo, Santa Cruz
Outside California: to British Columbia, Nova Scotia, Florida, Mexico to South America
Bloom period
Schoenoplectus americanus blooms Summer.
How to tell it apart
vs Juncus: Schoenoplectus has flowers in spikelets with overlapping scales; Juncus has separate flowers with 6 perianth parts.; vs Typha: Schoenoplectus has small spikelets of tiny flowers; Typha has dense brown cylindrical flower spikes (cattails).; vs Bolboschoenus: Schoenoplectus has smooth flower scales; Bolboschoenus scales are fuzzy-hairy.; vs Carex: Schoenoplectus has bisexual flowers in open spikelets; Carex has separate male/female flowers in enclosed sacs.; vs Scirpus: Schoenoplectus has dull bracts with notched tips; Scirpus bracts are pointed and often reddish-tinged.
Frequently asked questions
Is Schoenoplectus americanus native to California?
Yes. Schoenoplectus americanus is native to California (recorded as native).
When does Schoenoplectus americanus bloom?
Schoenoplectus americanus blooms Summer.
Where in California does Schoenoplectus americanus grow?
Schoenoplectus americanus occurs in San Bernardino, San Diego, Los Angeles, Riverside, Orange, Imperial, Inyo, Kern and other counties, at elevations of < 2200 m.
What plant family does Schoenoplectus americanus belong to?
Schoenoplectus americanus is in the Cyperaceae family, genus Schoenoplectus.
What habitat does Schoenoplectus americanus grow in?
Schoenoplectus americanus grows in Mineral-rich or brackish marshes, shores, fens, springs.
Related species
Other California species in the same genus, family, or bioregion.
- Schoenoplectus californicus — Southern bulrush
- Schoenoplectus heterochaetus — Slender bulrush
- Schoenoplectus mucronatus — Rough-seed bulrush
- Schoenoplectus pungens var. longispicatus — Common three-square bulrush
- Schoenoplectus saximontanus — Rocky mountain bulrush
- Schoenoplectus sp. — Naked-stemmed bulrushes
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.