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Taxon  Report  
Achyronychia cooperi  Torr. & A. Gray
Frost mat,   Onyxflower
Achyronychia cooperi is an annual herb that is native to California, and also found elsewhere in western North America.
Siskiyou Del Norte Modoc Humboldt Shasta Lassen Trinity Plumas Tehama Butte Mendocino Glenn Sierra Yuba Lake Nevada Colusa Placer Sutter El Dorado Yolo Alpine Napa Sonoma Sacramento Mono Amador Solano Calaveras Tuolumne San Joaquin Marin Contra Costa Alameda Santa Cruz Mariposa Madera San Francisco San Mateo Merced Fresno Stanislaus Santa Clara Inyo San Benito Tulare Kings Monterey San Bernardino San Luis Obispo Kern Santa Barbara Ventura Los Angeles Riverside Orange San Diego Imperial
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Bloom Period
Genus: Achyronychia
Family: Caryophyllaceae  
Category: angiosperm  
PLANTS group:Dicot
Jepson eFlora section: eudicot

Communities: Creosote Bush Scrub
Name Status:
Accepted by JEF + JEF + PLANTS + POWO

Information about  Achyronychia cooperi from other sources
Nursery availability from CNPLX
Commercial availability unknown.
Jepson eFlora

USDA PLANTS Profile (ACCO3)

Photos on Calflora

Photos on CalPhotos

Google Images

Photos on iNaturalist

ID Tips on PlantID.net

[Wikipedia] Monotypic Genus, Range: Achyronychia is a monotypic genus of flowering plant containing the single species Achyronychia cooperi, which is known by the common names onyxflower and frost-mat. This plant is native to the Mojave and Sonoran Deserts of northern Mexico and the U.S. states of California, Nevada, Utah and Arizona. In California, it is known from San Diego, Imperial, Riverside, Los Angeles, San Bernardino and Inyo Counties. In Arizona, it occurs in Yuma, Mohave, Pima, Pinal and Maricopa Counties. It has also been reported from Washington County in Utah, and from Clark County, Nevada.[ (link added by Mary Ann Machi)


Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals. [web application]. 2025. The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 05/13/2025).