Plants annual or perennial, her-baceous, pubescent to stipitate-glandular (especially in inflore-scences), not glaucous. Stems erect or ascending, simple or sparingly branched throughout, 5-35 cm. Leaves opposite; stipules persistent, divided into 2 filiform segments, 0.5-1 mm; petiole 1-8 mm; blade ovate to reniform, 0.5-1.5(-2) cm × 4-17(-25) mm, base truncate to cordate, apex acute to cuspidate. Inflorescences terminal, usually congested, 3-15-flow-ered clusters terminating branches of cymes. Pedicels shorter to longer than subtending bracts at maturity. Flowers: sepals with 3 distinct, usually prominent veins arcing outward at midsection and ± confluent apically, lanceolate (herbaceous portion similar), 3-4.8 mm, subequal or outer sepals shorter than inner, apex acute to setaceous-acuminate (herbaceous portion similar), not hooded, glabrous or stipitate-glandular; petals 2-fid for 2+ their length, 1.2-3.2 mm, equaling or shorter than sepals, lobes 1-veined, vein unbranched, lanceolate, trunk absent, base gradually tapered, apex ± rounded. Seeds tan to reddish brown, snail-shell-shaped, 0.5-0.7 mm; tubercles prominent, rounded.

Flowering late summer-early fall. Woodlands of mountainous areas; 1500-2300 m; Ariz., N.Mex.; Mexico (Chihuahua, Coahuila, Nuevo León, San Luis Potosí, Sonora).