Annuals, 1-20 cm (across or high); herbage not scented. Stems prostrate to ascending (often mat-forming, densely leafy distally), puberulent (in decurrent lines or throughout) or glabrate. Leaves (bluish green) linear to linear-oblanceolate or narrowly oblong, 10-30 × 1.5-4 mm, margins with 2-5 pairs of setae 1-2 mm, faces glabrous (abaxial densely dotted with scattered, circular oil-glands 0.05-0.2 mm). Heads borne singly or in congested, (leafy) cymiform arrays. Peduncles 1-5 mm. Involucres cylindric. Phyllaries coherent (falling together), oblong to oblong-obovate, 6-10 × 2-3 mm (dotted with scattered, elliptic oil-glands 0.05-0.15 mm). Ray florets 3(-4); corollas 3-4 mm (scarcely surpassing phyllaries). Disc florets (3-)7-14; corollas 2.2-2.6 mm (2-lipped). Cypselae 4-5.5 mm, puberulent (distally glandular-puberulent); pappi of 2 (ray) and 5 (disc) lanceolate scales 1.5-3.5 mm. 2n = 48. Flowering Jul-Nov. Deserts, oak-juniper woodlands, grasslands, wash channels, mud flats, lawns, roadsides; 700-1500 m; Ariz., N.Mex., Tex.; Mexico (Baja California Sur, Chihuahua, Coahuila, Durango, Nuevo León, Sinaloa, Sonora). Pectis cylindrica (2n = 48) is similar to P. prostrata (2n = 24); the two occasionally grow together (D. J. Keil 1975b). Some herbaria contain mixed collections of the two. No evidence is available of hybrids between the two.

Plant: Low diffuse annual forb usually less than 10 cm Leaves: leaves opposite, linear-oblong, 1-2 cm long, gland-dotted Flowers: flowers heads 9 mm high, sessile, much surpassed by the leaves, phyllaries 3, in one series; yellow ray flowers only; pappus of 2-6 scarious palea.