PLANT: Herbs. STEMS: erect, unbranched, 40-80 cm tall, glabrous to rather glaucous. LEAVES: opposite or the bractealleaves subtending the peduncles alternate, sessile, or the petioles to 2 mm long, the blades broadly oblong to ovate-elliptic, 3-16 cm long, (1-)2-7 cm broad, shallowly cordate and more or less clasping at the base, obtuse to rounded at the apex, apiculate, glabrous on both surfaces, glaucous beneath. UMBELS: 1 to several, subterminal at the uppermost nodes, finely pubescent, 5-7 cm broad, the peduncles 3-15 cm long. FLOWERS: large; calyx lobes 5-8 mm long; corolla green or with a touch of purple on the tips outside, tardily reflexed-spreading, the lobes 9-12 mm long; hoods yellowish with white margins, sessile and attached along almost the entire height of the column, ovoid-oblong and more or less -J”-shaped, horizontally spreading-saccate from the base, curved upward near the middle to an erect, truncate apex, ca. 4-5 mm long, 2-4 mm broad at the top, slightly shorter than the gynostegium, the horns radially flat, attached the full length of the hoods, triangular to sickle-shaped, mostly concealed within the hoods; anther wings 2.4-2.8 mm long; corpusculum 0.8-1 mm long, the pollinia 1.1-1.3 mm long. FOLLICLES: erect on deflexed pedicels, 11-15 cm long. NOTES: Canyons, rocky stream beds, open woodlands, mts. of se AZ: Cochise, Gila, Graham, Pima, Santa Cruz, cos.; 1200-2150 m (3900-7100 ft); Jul-Sep; s NM, sw TX; Mex. to Guatemala. REFERENCES: Sundell, Eric. 1994. Asclepiadaceae. J. Ariz. - Nev. Acad. Sci. Volume 27, 169-187.