Plant: shrub, 100-300(-400) cm tall; stems erect or ascending, wandlike, branching above, glabrous except on very young growth, conspicuously white-glaucous, in age leafless Leaves: opposite or in whorls of 3, narrowly linear, 1-3 cm long, early-deciduous INFLORESCENCE: UMBELS lateral at the upper nodes, 3-5 cm broad, the peduncles 1-3 cm long, sparsely hairy to glabrate, the pedicels more or less wooly Flowers: with the calyx lobes 3-4 mm long; corolla drying greenish white or flushed with pale purple, the lobes 6-9 mm long; hoods drying yellow brown, ascending, oblong-quadrate, 2-3 mm long, 1.6-2.4 mm broad, ca. 1 mm shorter than the gynostegium, the horns attached the full length of the hoods and free apically for ca. 2 mm, the free portion digitate, mostly straight, appressed to the hood apices, scarcely exserted toward the stigma head; anther wings 2 mm long; corpusculum 0.3 mm long, the pollinia 1.3-1.5 mm long Fruit: FOLLICLES pendulous on spreading to drooping peduncles and pedicels, 8-15 cm long Misc: Rocky desert flats and slopes; 150-750 m (500-2500 ft); Sep-Jun REFERENCES: Sundell, Eric. 1994. Asclepiadaceae. J. Ariz. - Nev. Acad. Sci. Volume 27, 169-187.
Nabhan et al 2015
Duration: Perennial Nativity: Native Lifeform: Subshrub General: A reed-like, erect plant that branches at its base into a few 5-9 foot tall, waxy, nearly leafless stems that produce umbels of pale flowers. The whitish to grayish-blue hue gives a waxy appearance to the wand-like stems, Leaves: Thread-like linear leaves arranged in pairs that are quickly shed with the onset of drought. Flowers: Creamy-white with black anthers, sometimes with a pink blush, fading yellow in ball-like clusters near and at the ends of tall stems. Fruits: 3 to 6 inch pendulous, canoe-shaped pods. Ecology: This desert milkweed prefers rocky, north-facing slopes of granitic ranges, although it also occurs on the walls of volcanic craters.; below 2,500 feet; flowers Mostly September to June but sometimes year-around, depending upon rains Distribution: w and sw AZ, se CA and four Mexican states. Notes: Relatively new to commercial cultivation because of its vulnerability to freezes, it has been successfully grown in desert botanical gardens and outdoor museums for decades. It can be distinguished from its close kin in the same desert region, A. subulata, by its fewer, longer, thicker, more noticeably waxy-blue stems, the very short nectar cups of the flowers, and its preference for rocky uplands rather than fine-textured substrates on playas, dunes or low sandy hummocks. This is a known monarch host plant. Synonyms: None Editor: AHazelton 2015