Arnica sororia

Twin arnica, Twin Arnica

Family: Asteraceae · Type: perennial · Native

Twin arnica is a California native perennial found in the Great Basin in open sagebrush scrub at elevations of 1,400 to 1,800 meters. Flowering from May to July, this plant produces yellow-orange ray flowers in radiate heads 10 to 15 millimeters wide. Growing with stems 10 to 50 centimeters tall, emerging from a short, sparsely scaly rhizome, the plant can be single or branched with stalked-glandular and uneven hairiness. Its basal leaves are densely clustered, with oblanceolate blades 3.5 to 14.5 centimeters long, while cauline leaves are 3 to 6 pairs and crowded toward the base. The fruit is 3 to 5.5 millimeters long, covered in hairs and topped with a short-barbed white pappus.

Habitat: Uncommon. Open sagebrush scrub

Bloom period: May-Jul

Elevation: 1400-1800 m

Bioregions: GB

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