Bromus secalinus
Rye brome, Rye Brome
(c) Ульяна Лалак, some rights reserved (CC BY) · licence
Family: Poaceae · Type: Grass · Not Native
Bromus secalinus (Rye brome) is a non-native California grass in the Poaceae family, recognized by distinctive widening spikelets in fruit with visible stalks.
Rye brome is a naturalized annual grass found in northwestern California, the California Cascades, northern Sierra Nevada, northern San Francisco Bay Area, San Bernardino Mountains, and Modoc Plateau in open, disturbed areas at elevations below 1,500 meters. Flowering from May to July, this grass produces delicate, spreading inflorescences 8 to 17 centimeters long with nodding branches that become increasingly visible as the spikelets mature. Growing 45 to 100 centimeters tall with ascending stems, it develops open, spreading seed clusters that widen as the fruits develop. Its leaves are 4 to 12 millimeters wide, covered in soft hairs, with glabrous or lightly hairy leaf sheaths. The spikelets measure 12 to 24 millimeters long, with glabrous glumes and lemmas that may be smooth or slightly hairy, occasionally featuring awns up to 9.5 millimeters long.
Identification and appearance
Key characters: 32 sympatric species; distinctive widening spikelets in fruit with visible stalks
Habitat and range
Habitat: Open, disturbed areas
Elevation: < 1500 m
California counties: San Bernardino, El Dorado, Lake, Los Angeles, Shasta, Lassen, Tuolumne, Sierra, Plumas, Nevada, Butte, Siskiyou, Humboldt, Mariposa, Fresno, Mendocino, Marin, Modoc, Sonoma, Monterey, Del Norte, Placer
Outside California: to British Columbia, eastern United States, Veracruz, native to Europe
Bloom period
Bromus secalinus 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 secalinus native to California?
No. Bromus secalinus is not native to California (recorded as not native).
When does Bromus secalinus bloom?
Bromus secalinus blooms May-Jul.
Where in California does Bromus secalinus grow?
Bromus secalinus occurs in San Bernardino, El Dorado, Lake, Los Angeles, Shasta, Lassen, Tuolumne, Sierra and other counties, at elevations of < 1500 m.
What plant family does Bromus secalinus belong to?
Bromus secalinus is in the Poaceae family, genus Bromus.
What habitat does Bromus secalinus grow in?
Bromus secalinus grows in Open, disturbed areas.
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.