Mohave sulphur flower

Herbs, spreading mats, 0.5-2 × 1-3 dm. Aerial flowering stems spreading to erect, (0.3-)0.5-1.5(-2) dm, floccose, without one or more leaflike bracts ca. midlength. Leaves mostly in tight rosettes; blade narrowly elliptic, 0.7-2.5 × 0.3-1 cm, thinly floccose on both surfaces or glabrous adaxially, margins plane. Inflorescences umbellate; branches 2.5-8 cm, thinly floccose or glabrous, without a whorl of bracts ca. midlength; involucral tubes 2-3 mm, lobes 1.5-3 mm. Flowers 3-7 mm; perianth bright yellow.

Flowering May-Jun. Sandy to gravelly flats and slopes, sagebrush communities, oak, pinyon-juniper, and montane conifer woodlands; 1200-1600 m; Ariz.

Variety mohavense is known only from the Black Rock and Wolf Hole mountains area on the Arizona Strip of Mohave County, Arizona. The rays or branchlets of the inflorescences are rather long (2.5-8 cm). The taxon is related to the much more widely distributed, late-season-flowering var. subaridum found to the north and west.