Allium unifolium

One leaf onion

Family: Alliaceae · Type: perennial · Native

One leaf onion is a California native perennial found in northwestern and central western California in moist clay or serpentine areas, especially grassy streambanks at elevations below 1,100 meters. Flowering from May to June, this plant produces delicate pink or white flowers in clusters of 15 to 35 blooms with pedicels 15 to 40 millimeters long. Growing with slender stems 30 to 80 centimeters tall, it develops from a small ovoid bulb with 1 to 3 obvious rhizomes that produce new bulbs at their tips. Its leaves are 2 to 3 in number, shorter than the stem, widely channeled or nearly flat, and keeled. The bulb has a pale brown outer coat with subtle rectangular cell patterns.

Habitat: Uncommon. Moist clay or serpentine, especially grassy streambanks

Bloom period: May-Jun

Elevation: < 1100 m

Bioregions: NW, CW

California counties: Lake, Monterey, San Francisco, Humboldt, Santa Cruz, Mendocino, Santa Clara, Napa, San Luis Obispo, Stanislaus, San Mateo, Contra Costa, Alameda, Riverside, Del Norte, San Benito, Marin, Sonoma, San Diego

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.