Plant: Perennial rhizomatous herb, erect or ascending, unbranched or branching, frequently also with dwarf, lateral shoots in at least some of the leaf axils, 20-100 cm tall, glabrous or finely pubescent above; milky sap Leaves: whorled, mostly 3 or 4 per node, subsessile, the petioles 1-4 mm long, the blades linear, 2-12 cm long, ca. 1-4 mm broad, attenuate and acute at apex and base, essentially glabrous on both surfaces, the margins more or less revolute INFLORESCENCE: UMBELS lateral to subterminally crowded, single or paired at the upper nodes, 2-4 cm broad, the peduncles mostly 1-5 cm long Flowers: small; calyx lobes ca. 2 mm long; corolla white, greenish, or grayish purple, the lobes 4-5 mm long; hoods white or yellowish, erect-ascending, quadrate to oblong-obovoid, 1.4-2.4 mm long, 0.8-1.6 mm broad at the truncate to oblique rim, about as long as to 1 mm shorter than the gynostegium, the horns radially flat, attached near the base of the hoods, exserted 1-2 mm and arching over the stigma head; anther wings 1.4-1.6 mm long; corpusculum ca. 0.25 mm long, the pollinia 0.8-1.2 mm long Fruit: FOLLICLES erect on erect pedicels, 6-12 cm long Misc: Open woodlands, grasslands, stream terraces, invading roadsides, pastures, yards and gardens; 950-2400 m (3100-7800 ft); Jun-Sep REFERENCES: Sundell, Eric. 1994. Asclepiadaceae. J. Ariz. – Nev. Acad. Sci. Volume 27, 169-187.