Portulaca villosa is a perennial succulent herb in the Portulacaceae (purslane) family, with a fleshy to woody, tuberous taproot. Stems are prostrate to weakly ascending and can extend outward approximately 30 cm (1 ft) in length. Leaves are pale grayish green, narrowly oblanceolate (longer than wide, widest toward the tip) to linear and subterete (somewhat cylindrical). Leaves are approximately 5 to 25 mm (0.2 to 1 in) long and 1.5 to 3 mm (0.06 to 0.1 in) wide, sessile, with a dense tuft of yellowish brown hairs in the leaf axil, 1 to 12 mm (0.04 to 0.5 in) long. Flowers are white, pink, or pink with a white base. Flowers are clustered (3 to 6) in dense, terminal, head-like cymes subtended by dense tufts of hairs 6 to 12 mm (0.2 to 0.5 in) long and a series of involucrate leaves (below the flower) with bracteoles (stalked bracts) approximately1.5 mm (0.06 in) long; petals obovate, 8 to 10 mm (0.3 to 0.4 in) long; sepals 4 to 5 mm (0.16 to 0.2 in) long with thin, dry, somewhat translucent membranous margins; stamens 18 to 50; style 5- to 7- or 8-branched. Capsules are broadly ovoid, 3 to 5 mm (0.1 to 0.2 in ) long. Seeds are dark reddish brown, 0.6 to 0.7 mm (0.02 to 0.03 in) long, with a stellulate-rugose (star-shaped-wrinkled) surface.