Bromus commutatus
Hairy chess, meadow brome, Meadow Brome
(c) Zihao Wang, some rights reserved (CC BY) · licence
Family: Poaceae · Type: Annual · Not Native
Bromus commutatus (Hairy chess) is a non-native California annual in the Poaceae family, recognized by broad inflorescence and hairy lower sheaths diagnostic.
Hairy chess is a naturalized annual grass found in northwestern California, the Cascade Range, northern Sierra Nevada, central and southern Sierra Nevada, eastern Sierra Nevada, Sacramento Valley, central coastal California, San Francisco Bay Area, and Great Basin in disturbed areas at elevations below 2,200 meters. Flowering from May to July, this plant produces pale green to tan spikelets 15 to 30 millimeters long in broad, spreading inflorescences. Growing with erect stems 40 to 120 centimeters tall, it has long, soft lower leaf sheaths and blades 3 to 9 millimeters wide. Its leaves feature a small ligule 1 to 4 millimeters long, with lower sheaths distinctly hairy. The spikelets have lemmas with awns 4 to 10 millimeters long, creating a delicate, feathery appearance when mature.
Identification and appearance
Key characters: 29 sympatric species; broad inflorescence and hairy lower sheaths diagnostic
Habitat and range
Habitat: Disturbed areas
Elevation: < 2200 m
Outside California: to British Columbia, eastern North America, native to Europe
Bloom period
Bromus commutatus blooms May-Jul.
How to tell it apart
vs Nassella: Bromus has closed leaf sheaths and large spikelets; Nassella has open sheaths and needle-like awns.; vs Hordeum: Bromus has separate large spikelets; Hordeum has three spikelets grouped at each node.; vs Avena: Bromus lemmas have two teeth at tip; Avena lemmas have a twisted awn from the back.; vs Lolium: Bromus spikelets are stalked in clusters; Lolium spikelets sit edgewise against the stem.; vs Festuca: Bromus leaf sheaths are closed; Festuca sheaths split open halfway down.
Frequently asked questions
Is Bromus commutatus native to California?
No. Bromus commutatus is not native to California (recorded as not native).
When does Bromus commutatus bloom?
Bromus commutatus blooms May-Jul.
What plant family does Bromus commutatus belong to?
Bromus commutatus is in the Poaceae family, genus Bromus.
What habitat does Bromus commutatus grow in?
Bromus commutatus grows in Disturbed areas.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-06
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.