Aira caryophyllea
Silver hair grass, Silver Hair Grass
(c) Leon Perrie, some rights reserved (CC BY) · licence
Family: Poaceae · Type: Grass · Not Native
Aira caryophyllea (Silver hair grass) is a non-native California grass in the Poaceae family, recognized by . Key features: largest size, highest elevation range, open inflorescence with equal branches, spikelet stalks 1-2x spikelet length.
Silver hair grass is a naturalized annual found in northwestern California, western Cascade Range, Sierra Nevada, Central Valley, central western California, and eastern southwestern California in sandy soils and open or disturbed sites at elevations below 1,900 meters. Flowering from April to June, this grass produces delicate, silvery-white flower clusters in open panicles up to 1.5 centimeters wide. Growing with slender stems 6 to 45 centimeters tall that are generally smooth and occasionally slightly hairy near the nodes, it has a delicate, airy appearance. Its leaf sheaths are slightly rough with short, minutely scabrous ligules, and the narrow grass blades emerge in a light, feathery manner. The small spikelets are 2.4 to 3.5 millimeters long, with slender awns approximately 3 millimeters in length.
Identification and appearance
Key characters: 2 sympatric species. Key features: largest size, highest elevation range, open inflorescence with equal branches, spikelet stalks 1-2x spikelet length
Habitat and range
Habitat: Sandy soils, open or disturbed sites
Elevation: < 1900 m
California counties: Humboldt, San Luis Obispo, Butte, Calaveras, Contra Costa, Del Norte, Fresno, Lake, Los Angeles, Marin, Mariposa, Mendocino, Monterey, Placer, Sacramento, San Benito, San Diego, San Francisco, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Sonoma, Sutter, Tehama, Trinity, Tulare, Tuolumne, El Dorado, Riverside, Siskiyou, Kern, Yuba, Madera, Nevada, Amador, Colusa, Solano, Napa, Alameda, Shasta, Plumas, Stanislaus, Modoc, Yolo, Mono
Outside California: to British Columbia, eastern United States, Baja California, native to Europe
Bloom period
Aira caryophyllea blooms Apr-Jun.
How to tell it apart
vs Briza: Aira has delicate linear spikelets; Briza has distinctive heart-shaped, dangling spikelets.; vs Eriocoma: Aira is a tiny silvery annual; Eriocoma is a robust perennial bunchgrass with twisted awns.; vs Vahlodea: Aira is annual with no axis extension; Vahlodea is perennial with tiny axis extension.; vs Deschampsia: Aira is annual and delicate; Deschampsia is perennial, often forming dense tufts.; vs Trisetum: Aira has no axis extension beyond flowers; Trisetum has a hairy bristle extending beyond.
Frequently asked questions
Is Aira caryophyllea native to California?
No. Aira caryophyllea is not native to California (recorded as not native).
When does Aira caryophyllea bloom?
Aira caryophyllea blooms Apr-Jun.
Where in California does Aira caryophyllea grow?
Aira caryophyllea occurs in Humboldt, San Luis Obispo, Butte, Calaveras, Contra Costa, Del Norte, Fresno, Lake and other counties, at elevations of < 1900 m.
What plant family does Aira caryophyllea belong to?
Aira caryophyllea is in the Poaceae family, genus Aira.
What habitat does Aira caryophyllea grow in?
Aira caryophyllea grows in Sandy soils, open or disturbed sites.
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.