Plants herbaceous, often slightly woody at base, overall pubescence of white, capitate hairs 0.2-0.4 mm. Stems ascending to prostrate or sprawling, profusely branched, to 100 cm, puberulent to glabrate, occasionally hirtellous. Leaves grayish green, petiolate, those of pair slightly unequal; petiole 1-14 mm, puberulent to glabrate; blade lanceolate to linear-lanceolate or triangular-lanceolate to deltate, 3-40 × 1-30 mm, base cuneate and decurrent, margins undulate or crispate, apex acuminate to acute or long attenuate, glaucous, puberulent to glabrate. Inflorescences solitary flowers, rarely geminate, sessile or with pedicel to 7 mm; bracts linear-subulate, 1-7 mm, puberulent to sparsely so. Flowers: chasmogamous perianth with tubes 7-17 cm × 1-2 mm, puberulent to glabrate, limbs 10-20 mm diam., stamens 5; cleistogamous perianth 5-12 mm, puberulent, stamens 5. Fruits with 5 hyaline ridges and pair of shallow, parallel grooves between ridges, without resinous glands, narrowly oblong, truncated at both ends, constricted 1 mm both below apex and above base, 6-10 mm, hirtellous to puberulent with capitate hairs and many to few, minute, moniliform hairs 0.2-0.4 mm, or glabrate. Flowering Feb-Nov. Rocky, gravelly, loamy, or sandy calcareous, gypseous, or igneous-derived soils in deserts, grasslands, shrublands, or woodlands; 0-2500 m; Ariz., Calif., N.Mex., Tex.; Mexico (Chihuahua, Coahuila, Durango, Nuevo León, Sonora, Tamaulipas).

Notes: flowers with one whorl, appearing petaloid References: J.C. Hickman, ed. The Jepson Manual. A. Cronquist. An integrated system of classification of flowering plants. ASU specimens.