Plant: perennial herb; stems erect or ascending, unbranched, 20-80 cm tall, short woolly to more or less glabrate; milky sap Leaves: opposite, subsessile or the petioles to 10 mm long, the blades nearly circular to mostly broadly elliptic, 5-14 cm long, 4-12 cm broad, broadly rounded to subcordate at the base, broadly rounded to truncate or retuse at the apex, apiculate, short woolly when young, in age more or less glabrate on both surfaces INFLORESCENCE: UMBELS lateral at most of the upper nodes, persistently short woolly, (4-)5-8 cm broad, subsessile or the peduncles to 2(-3) cm long Flowers: large; calyx lobes ca. 4 mm long; corolla greenish, the lobes 7-10 mm long; hoods whitish to yellow-brown, erect or uncommonly ascending, mostly oblong-quadrate, truncate at the apex, 3-4 mm high, 2-3 mm broad, about as long as the gynostegium, the horns radially flat, fused nearly the full length of the hoods, triangular to sickle-shaped, abruptly incurved and short-exserted; anther wings 2.7-3.2 mm long; corpusculum 0.4-0.5 mm long, the pollinia 1.7-1.9 mm long Fruit: FOLLICLES erect on deflexed pedicels, 7-9 cm long Misc: Canyons and rocky slopes, desert grasslands, spreading to roadsides; 750-2150 m (2500-7000 ft); Jun-Sep REFERENCES: Sundell, Eric. 1994. Asclepiadaceae. J. Ariz. - Nev. Acad. Sci. Volume 27, 169-187.