Plants 3-10 dm. Aerial flowering stems not fistulose, (1.5-)2-4 dm, glabrous. Leaves basal; blade 1-5 × 0.5-2 cm, tomentose abaxially, thinly floccose or glabrous adaxially, margins plane. Inflorescences cymose, 20-50 cm; branches glabrous. Involucres 2-5 per cluster, 3-5 mm, glabrous or sparsely pubescent. Flowers 2-3 mm; perianth white, rarely yellow, glabrous. 2n = 40.

Flowering Jun-Sep. Sandy to gravelly flats, slopes, banks, and washes, mixed grassland and chaparral communities, oak and conifer woodlands; 10-2100(-2400) m; Calif., Oreg., Wash.

Variety nudum is the low-elevation tetraploid expression of the species, found mainly in the Coast Ranges and interior valleys from southern Washington through Oregon to California. It is replaced by var. deductum at higher elevations in the Sierra Nevada. Yellow-flowered populations occur rarely in the Siskiyou Mountains of California and Oregon.