Plant: perennial herb; stems erect, unbranched, 40-100 cm tall, densely white woolly to pubescent when young, more or less glabrate below Leaves: opposite, the petioles 4-10 mm long, the blades ovate to broadly lanceolate, 7-20 cm long, 2-9 cm broad, obtuse to broadly rounded or rarely subcordate at the base, attenuate to an obtuse or acute apex, pubescent above, rather woolly beneath INFLORESCENCE: UMBELS lateral at the upper nodes, 4-9 cm broad, the peduncles 2-11 cm long Flowers: large; calyx lobes 4-6 mm long; corolla purplish, the lobes 9-11 mm long; hoods drying yellow-brown, ascending, ovoid-attenuate, more or less abruptly narrowed near the middle, 10-14 mm long, 5-10 mm longer than the gynostegium, the horns attached near the base of the hoods, radially flat, exserted 1-2 mm and incurved over the stigma head; anther wings 2.4-3 mm long; corpusculum 0.7-0.8 mm long, the pollinia 1.3-1.6 mm long Fruit: FOLLICLES erect on deflexed pedicels, 11-13 cm long, the surface typically with soft, elongate tubercles Misc: Mountain meadows and open woodlands, streamsides, spreading to roadsides and other disturbed sites; 1500-2600 m (5000-8500 ft); Jun-Aug REFERENCES: Sundell, Eric. 1994. Asclepiadaceae. J. Ariz. – Nev. Acad. Sci. Volume 27, 169-187.