Plant: perennial herb; stems erect, unbranched or with a few lateral shoots from the middle and upper nodes, 20-70 cm tall, finely pubescent in lines above the petioles or becoming glabrous Leaves: opposite, subsessile, the petioles 1-6 mm long, the blades linear to narrowly lanceolate or elliptic, 4-12 cm long, 2-11(-15) mm broad, attenuate at apex and base, glabrous on both surfaces, or with a few hairs on the margins and midvein below Inflorescence: UMBELS lateral in the upper portion of the stem, one per node, or infrequently single and appearing terminal, 2-3 cm broad, the peduncles 1-6 cm long Flowers: small; calyx lobes ca. 2.5 mm long; corolla white or flushed with pale purple, the lobes 5-6 mm long; hoods white, erect-ascending, obovoid-oblong, 2.5-3.4 mm long, 1.6-2.2 mm broad along the sloping apex, about as long as to slightly longer than the gynostegium, obtuse-rounded above, the horns digitate, attached near the base of the hoods, exserted ca. 2 mm and arching over the stigma head; anther wings 1.6-2 mm long; corpusculum ca. 0.2 mm long, the pollinia 1.1-1.2 mm long Fruit: FOLLICLES erect on erect pedicels, 5-9 cm long Misc: Riparian woodlands and canyons, mts; 1050-1750 m (3500-5700 ft); May-Aug REFERENCES: Sundell, Eric. 1994. Asclepiadaceae. J. Ariz. – Nev. Acad. Sci. Volume 27, 169-187.