Perennials or subshrubs (shrubs), 60-100 cm. Stems mostly sparsely puberulent (hairs upcurved or apically bent). Leaves mostly opposite, sometimes subopposite to alternate on distal 1/3 of stems; petioles 2-8(-12) mm; blades lanceolate, mostly 3-8(-11) × 1-3 cm, bases rounded, margins entire or shallowly crenate, apices acuminate, abaxial faces eglandular, adaxial glabrous. Involucres 4.5-5.5 mm. Phyllaries: outermost narrowly lanceolate, glabrous, margins hyaline on proximal 2/3, eciliate. Corollas usually white, sometimes purple-tinged to yellowish, 2.5-3 mm, lobes glandular. Cypselae 1.8-2.8 mm, sparsely hispidulous. 2n = 20. Flowering (Jun-)Sep-Nov(-Dec). Canyon walls, ledges, slopes, talus, limestone hills and ridges, on and among rocks, in woods along streams; 700-1600 m; Tex.; Mexico (Chihuahua, Coahuila, Durango, Zacatecas).
