Bromus japonicus
Japanese chess, japanese brome, Japanese Brome
(c) Rosario Douglas, some rights reserved (CC BY) · licence
Family: Poaceae · Type: Annual · Not Native
Conservation status: Cal-IPC Yes
Bromus japonicus (Japanese chess) is a non-native California annual in the Poaceae family, recognized by wavy branches and awn position diagnostic.
Japanese chess is a naturalized annual grass found throughout California in open, disturbed areas at elevations below 2,470 meters. Flowering from May to July, this grass produces pale green to tan spikelets 20 to 40 millimeters long with delicate spreading branches. Growing 17 to 85 centimeters tall with upright to slightly wavy stems, it has distinctive branching that creates an open, loose appearance. Its leaves have hairy sheaths and blades 1.5 to 6 millimeters wide, with each leaf blade varying from glabrous to slightly hairy. The grass produces slender awns 5 to 11 millimeters long, extending slightly curved from each spikelet.
Identification and appearance
Key characters: 34 sympatric species; wavy branches and awn position diagnostic
Habitat and range
Habitat: Open, disturbed areas
Elevation: < 2470 m
California counties: Butte, Inyo, Lake, Modoc, Plumas, San Bernardino, San Luis Obispo, Los Angeles, Riverside, Sierra, Siskiyou, Lassen, Colusa, Kern, Tuolumne, Tulare, Alpine, San Diego, Shasta, Glenn, Napa, Mariposa, Yuba, Santa Barbara, Nevada, Sonoma, Fresno, Calaveras, Tehama, Mono, Santa Cruz, San Benito, Yolo, Humboldt, Monterey
Outside California: mainland Mexico, to British Columbia, eastern North America, native to Eurasia
Bloom period
Bromus japonicus blooms May-Jul.
Conservation status
Cal-IPC Yes
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 japonicus native to California?
No. Bromus japonicus is not native to California (recorded as not native).
When does Bromus japonicus bloom?
Bromus japonicus blooms May-Jul.
Where in California does Bromus japonicus grow?
Bromus japonicus occurs in Butte, Inyo, Lake, Modoc, Plumas, San Bernardino, San Luis Obispo, Los Angeles and other counties, at elevations of < 2470 m.
What plant family does Bromus japonicus belong to?
Bromus japonicus is in the Poaceae family, genus Bromus.
Is Bromus japonicus invasive in California?
Bromus japonicus is listed by Cal-IPC with an invasiveness rating of Yes.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-06
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.