Avena fatua
Wild oat
Photo by Chez Brungraber
Family: Poaceae · Type: Grass · Not Native
Conservation status: Cal-IPC Yes
Avena fatua (Wild oat) is a non-native California grass in the Poaceae family, recognized by size, spikelet breaking, and callus characteristics.
Wild oat is a naturalized annual grass found in the California Floristic Province, Modoc Plateau, and Mojave Desert in disturbed sites at elevations below 2,400 meters. Flowering from April to June, this plant produces pale yellow to tan-colored flowers in distinctive open, drooping spikelets with long, twisted awns. Growing with erect stems 30 to 160 centimeters tall, it develops prominent branching flower clusters that arch and sway in the wind. Its leaves are long and narrow, with blade-like sections 10 to 45 centimeters in length and 4 to 15 millimeters wide, featuring smooth margins. The plant is characterized by its complex flower structure with bearded bases and lemmas that have dramatically bent and twisted awns up to 40 millimeters long.
Identification and appearance
Key characters: 3 sympatric species; key features are size, spikelet breaking, and callus characteristics
Habitat and range
Habitat: Disturbed sites
Elevation: < 2400 m
California counties: Los Angeles, San Luis Obispo, Kern, San Diego, Riverside, Orange, San Bernardino, Alameda, Amador, Butte, Contra Costa, Fresno, Humboldt, Imperial, Lake, Monterey, San Mateo, Santa Barbara, Santa Clara, Sonoma, Trinity, Tulare, Ventura, Yolo, Madera, Napa, San Francisco, Solano, Inyo, Sacramento, El Dorado, Colusa, Sutter, Calaveras, Glenn, Nevada, San Joaquin, Placer, Yuba, Plumas, Kings, Marin, Mariposa, Santa Cruz, Tuolumne, Tehama, Merced, Mendocino, Lassen, Stanislaus, Modoc, Siskiyou, Shasta, San Benito
Outside California: to Alaska, eastern Canada, most of United States, native to Eurasia
Bloom period
Avena fatua blooms Apr-Jun.
Conservation status
Cal-IPC Yes
How to tell it apart
vs Bromus: Avena has large dangling spikelets (15-50mm); Bromus has smaller, more upright or nodding spikelets under 20mm.; vs Danthonia: Avena has huge pendulous spikelets over 15mm; Danthonia has compact spikelets under 15mm.; vs Ehrharta: Avena has large dangling spikelets with twisted awns; Ehrharta has small awned spikelets and distinctive hardened lower florets.; vs Nassella: Avena has broad, dangling spikelets; Nassella has narrow, needle-like rolled florets with persistent awns.; vs Festuca: Avena has huge dangling spikelets (15-50mm); Festuca has small spikelets under 12mm in upright clusters.
Frequently asked questions
Is Avena fatua native to California?
No. Avena fatua is not native to California (recorded as not native).
When does Avena fatua bloom?
Avena fatua blooms Apr-Jun.
Where in California does Avena fatua grow?
Avena fatua occurs in Los Angeles, San Luis Obispo, Kern, San Diego, Riverside, Orange, San Bernardino, Alameda and other counties, at elevations of < 2400 m.
What plant family does Avena fatua belong to?
Avena fatua is in the Poaceae family, genus Avena.
Is Avena fatua invasive in California?
Avena fatua 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 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.