Amer. J. Sci. Arts, ser. 2, 15: 261. 1853.
Plants herbaceous, overall pubescence of white, capitate hairs 0.1–0.2 mm. Stems decumbent, much branched, 3–15 cm, puberulent to glabrate. Leaves grayish green, sessile or more often petioled, those of pair very unequal (1 leaf 2–10 times length of other); petioles of smaller leaves to 12 mm, those of larger leaves 2–35 mm, puberulent to glabrate; blade ovate to oval-oblong or oval-rhombic, base rounded to obtuse, unequal and short-decurrent, margins flat or very slightly undulate, apex acute to rounded or obtuse and apiculate, puberulent to glabrate; smaller blades 3–28 × 2–15 mm, larger blades 6–70 × 3–35 mm. Inflorescences solitary flowers, sessile or pedicellate; bracts linear-lanceolate to linear-subulate, 2–6 mm, sparsely puberulent; pedicel to 1 mm. Flowers: chasmogamous perianth 4–6 cm, puberulent, tube 10 mm diam., limbs 20–40 mm diam., stamens 5; cleistogamous perianth 1–3 mm, puberulent, stamens 5. Fruits with 10 equal ribs, without resinous glands, oval-oblong, truncate at both ends, slightly constricted beyond base, 3–6 mm, sparsely puberulent.
Phenology: Flowering spring–fall.
Habitat: Rocky, gravelly, or sandy soils, limestone or shale outcrops in grasslands or shrublands
Elevation: 40-3500 m
Tex., Mexico (Coahuila), Mexico (Nuevo León), Mexico (Tamaulipas)
"thin" is not a number."thick" is not a number.