Plant: perennial herb milky sap; 15 cm-1 m tall from a fleshy rhizome; stinging hairs on stems, leaves, and inflorescences, 4-8 mm long, transparent, each borne on a conspicuous, swollen, whitish base Leaves: more or less round in outline, 8-15 cm in diameter, 3-5-lobed to about the middle, pubescent when young but soon glabrate between the stinging hairs; base broadly cordate; margin incised-dentate with aristate teeth 1-2.5 cm long, sparsely ciliate; petioles 2-10 cm long, with two large yellowish glands at apex; stipules 5-6 mm long, deeply lobed INFLORESCENCE: terminal cymes Flowers: STAMINATE FLOWERS numerous; calyx funnel-shaped, 9-14 mm long, armed with stinging hairs; stamens 10, all connate, with a ring of hairs at the base; staminodes 3, thread-like. PISTILLATE FLOWERS few; sepals oblanceolate to spatulate, 10-12 mm long, with a few stinging hairs; ovary pubescent but glabrate; styles twice-branched Fruit: capsule, 10-12 mm long, the stinging hairs dense. SEEDS 9-11 mm long, 6-7 mm wide, 4-4.5 mm thick, rounded on the back, angled on the inner face, brown, sometimes mottled; caruncle whitish, fleshy, ca. 3 mm wide. Misc: Dry plains and hillsides in grassland, desertscrub, and oak woodland; 1100-1600 m (3600-5200 ft); May-Sep REFERENCES: Levin, Geoffrey A. Euphorbiaceae. Part 1. Acalypha and Cnidoscolus. J. Ariz. – Nev. Acad. Sci. 29(1): 18.