Contr. U.S. Natl. Herb. 12: 370. 1909.
Plants herbaceous, overall pubescence mixture of capitate-glandular hairs 0.2–0.3 mm and white, capitate, shorter hairs 0.1–0.2 mm. Stems decumbent to ascending, much branched, 10–40 cm, hirtellous to glabrate. Leaves yellowish green, usually petiolate, distalmost sessile or nearly so, those of pair subequal; petiole 1–15 mm, puberulent to hirtellous; blade oval to oblongelliptic, (5–) 10–50 × 3–20 (–25) mm, base acute to obtuse, margins crispate or undulate, apex apiculate and acute to obtuse or infrequently rounded; margins and adaxial midveins puberulent or occasionally hirtellous. Inflorescences solitary flowers, sessile or nearly so; bracts linear to subulate, 3–10 mm, hirtellous to puberulent. Flowers: chasmogamous perianth 2–5 cm, puberulent, tube 1–1.5 mm diam., limbs 10–30 mm diam., stamens 5; cleistogamous perianth 4–10 mm, hirtellous, stamens 2 (–5). Fruits with 5 narrow sulci and 5 broad, smooth ribs extending past glands, each bearing sticky, resinous gland in constriction below apex, ovate-oblong, constricted 0.5–1 mm below apex, 5–8 mm, base tapering, apex truncate, sparsely puberulent or glabrous.
Phenology: Flowering spring–fall.
Habitat: Calcareous or gypseous soils in grasslands and shrublands
Elevation: 700-2500 m
Tex., Mexico (Chihuahua), Mexico (Coahuila), Mexico (Durango), Mexico (Zacatecas)
"thick" is not a number.