Eriochloa acuminata var. acuminata
Southwestern cup grass, summer grass, Summer Grass
Stephen Laymon, Bureau of Land Management (via Wikimedia Commons) · CC0
Family: Poaceae · Type: Grass · Native
Eriochloa acuminata var. acuminata (Southwestern cup grass) is a native California grass in the Poaceae family, recognized by awnless upper glume and acuminate upper floret.
Southwestern cup grass is a California native perennial found in the Great Valley, southwestern California, and desert regions of southern California in seasonal stream habitats at elevations below 200 meters. Flowering from August to September, this grass produces small spikelets with awnless upper glumes, typically 4 to 6 millimeters long. Growing with stems 30 to 120 centimeters tall featuring 2 to 5 distinct nodes, it spreads with characteristic grass-like growth. Its leaf blades are 5 to 12 centimeters long and 5 to 12 millimeters wide, with surfaces that are glabrous or lightly short-hairy. The plant's inflorescence has a main axis 7 to 16 centimeters long, with primary branches 1 to 5 centimeters in length and spikelets typically arranged two per node.
Identification and appearance
Key characters: 2 sympatric species; key features are awnless upper glume and acuminate upper floret
Habitat and range
Habitat: Seasonal streams
Elevation: < 200 m
California counties: Butte, San Bernardino, Riverside, Fresno, San Joaquin, Sutter, Imperial, Kern, Sacramento, Yolo
Outside California: to southern United States, Baja California
Bloom period
Eriochloa acuminata var. acuminata blooms Aug-Sep.
How to tell it apart
vs Echinochloa: Eriochloa has spikelets in cups; barnyard grass has bristly spikelets without cups.; vs Digitaria: Eriochloa has each spikelet in a cup; crabgrass has spikelets without basal cups.; vs Paspalum: Eriochloa has spikelets sitting in cups; dallisgrass has spikelets without any cup structure.; vs Panicum: Eriochloa has a distinctive cup under each spikelet; panicgrass spikelets lack cups.
Frequently asked questions
Is Eriochloa acuminata var. acuminata native to California?
Yes. Eriochloa acuminata var. acuminata is native to California (recorded as native).
When does Eriochloa acuminata var. acuminata bloom?
Eriochloa acuminata var. acuminata blooms Aug-Sep.
Where in California does Eriochloa acuminata var. acuminata grow?
Eriochloa acuminata var. acuminata occurs in Butte, San Bernardino, Riverside, Fresno, San Joaquin, Sutter, Imperial, Kern and other counties, at elevations of < 200 m.
What plant family does Eriochloa acuminata var. acuminata belong to?
Eriochloa acuminata var. acuminata is in the Poaceae family, genus Eriochloa.
What habitat does Eriochloa acuminata var. acuminata grow in?
Eriochloa acuminata var. acuminata grows in Seasonal streams.
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.