Plants to 5 dm; roots tuberous, fleshily woody. Stems spreading-ascending, branching, suffru-tescent. Leaves sessile; blade subterete, to 3.5 cm. Inflores-cences cymose, overtopping leaves; peduncle not scapelike, to 1 cm. Flowers: sepals persistent, ovate, to 5 mm; petals pink, obovate, to 8 mm, apex short-acuminate; stamens 10; stigma 1, capitate. Capsules apically keeled along sutures, ellipsoid, to 6.5 mm. Seeds without arcuate ridges, to 1.3 mm. Flowering Jul-Aug. Pinyon-juniper and ponderosa pine communities in silicious conglomeritic gravel; of conservation concern; 2000-2500 m; Utah. Phemeranthus thompsonii is known only from Emery County. It is very similar to, and perhaps should be merged with, P. validulus, from which it differs mainly in having much shorter peduncles. When originally described, P. thompsonii was thought to differ also in having fewer stamens and longer leaves and petals, but in fact P.validulus sometimes has as few as six stamens, and has maximum leaf and petal lengths greater than those found in P. thompsonii.