Achyronychia cooperi

Onyx flower, frost-mat, Frost-Mat

Family: Caryophyllaceae · Type: annual · Native

Onyx flower is a California native annual found in southern California desert bioregions in sandy slopes, flats, and washes at elevations of 50 to 700 meters. Flowering from January to May, this delicate plant produces tiny white flowers in clusters of 20 to 60 blooms. Growing with prostrate to ascending stems 3 to 17 centimeters tall, it spreads in low, delicate patches across sandy terrain. Its leaves are oblanceolate, somewhat fleshy, and 3 to 20 millimeters long, with distinctive white-fringed scarious stipules. The fruit is a small utricle with 8 to 10 minute teeth, containing a single tan seed with a distinctive red dot near its narrow end.

Habitat: Sandy slopes, flats, washes

Bloom period: Jan-May

Elevation: 50-700 m

Bioregions: D

California counties: San Bernardino, Riverside, Imperial, Inyo, San Diego, Shasta, Kern

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