Herbs, perennial, monoecious, to 2.5 dm. Stems erect, sparsely hairy, hairs malpighiaceous. Leaves: stipules apparently persistent, punctiform, minute, margins glandular; petiole absent; blade elliptic, obovate, or linear, 1–5 × 0.5–2.2 cm, margins entire, without glands, surfaces sparsely hairy, hairs malpighiaceous. Inflorescences unisexual or bisexual, to 4 cm; bracts ovate to lanceolate, to 1.5 mm, margins without glands. Flowers without pink dye when wetted. Staminate flowers: sepals lanceolate, 3.5–7 × 1–1.3 mm; petals spatulate to obovate, 3–5 × 1.5 mm, adnate to androphore; nectary glands elliptic, 0.3 × 0.2 mm, adnate to androphore, glabrous; stamens (7–)10, staminodes 0 or rudimentary. Pistillate flowers: sepals lanceolate to ovate, 3.5–7 × 1.5–2.2 mm, without glands; petals 5, obovate to spatulate, 2.8–3.5 × 0.7–2.8 mm; nectary glands obovate, 0.5 × 0.7 mm, glabrous; ovary sericeous; styles 1.6–2 mm, glabrous; stigmas flattened. Capsules 3–5.5 mm, with scattered adpressed malpighiaceous hairs. Seeds 3.5–4 mm, smooth, maculate.
Phenology: Flowering Mar–Jun and Aug–Oct.
Habitat: Scrub, pinyon-juniper woodlands, limestone-derived, rocky soils, damp zones near lakes.
Elevation: 2000–2600 m.
Ariz., Nev., N.Mex.
Argythamnia cyanophylla is found from southern Nevada across northern Arizona to central New Mexico.