Plant: perennial herb; stems erect, typically unbranched, 60-120(-150) cm tall, glabrous to rather glaucous; milky sap Leaves: irregularly alternate to approximate, sessile, the blades linear, 5-25 cm long, 1-8 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, spreading-pubescent, 2-4 cm broad, sessile or the peduncles to 3.5 cm long Flowers: small; calyx lobes 3.5-5 mm long; corolla greenish or flushed with pale purple, the lobes 5-7 mm long; hoods sessile, curved-ascending, ovoid-oblong, 2.2-3 mm long, 0.9-1.5 mm broad in the middle, half to two-thirds as long as the gynostegium, truncate to retuse at the top, rounded-saccate at the base and with a pair of wing-like, rounded lobes spreading at right angles from the margins, the horns digitate, erect, attached near the middle of the hoods, ca. 1 mm long and scarcely exserted, or concealed within the hoods and variously reduced in length, or entirely absent and represented by a more or less distinct vertical ridge at the base of the back wall of the hoods; anther wings 2-2.4 mm long; corpusculum 0.6 mm long, the pollinia 1.2-1.3 mm long Fruit: FOLLICLES erect on deflexed pedicels, 7-12 cm long Misc: Creeks, canyons, open woodlands; 1050-2200 m (3500-7200 ft); Jun-Aug REFERENCES: Sundell, Eric. 1994. Asclepiadaceae. J. Ariz. – Nev. Acad. Sci. Volume 27, 169-187.