Plants to 4 dm; roots fleshily woody. Stems ascending or erect, simple or branching. Leaves sessile; blade subterete, to 7 cm. Inflorescences cymose, much overtopping leaves; peduncle scapelike, to 25 cm. Flowers: sepals persistent, ovate to suborbiculate, 4-6 mm; petals pink- to red-purple, obovate, 10-15 mm; stamens 25-45; stigma 1, subcapitate, 3-lobed. Capsules broadly ovoid, 6-7 mm. Seeds without arcuate ridges, 1 mm. 2n = 24, 48. Flowering May-Oct. Rocky or sandy soil, on or near outcrops; 100-1200 m; Ark., Colo., Ill., Kans., La., Mo., Nebr., N.Mex., Okla., Tex. Some populations of Phemeranthus calycinus are diploid while others are tetraploid, the latter probably the result of autopolyploidy (W. H. Murdy and M. E. B. Carter 2001).