PLANT: Suffrutescent, twining vines. STEMS: pubescent to glabrous, non-glandular. LEAVES: opposite. INFLORESCENCE: in ours umbelliform on well developed peduncles, with 5-30 flowers opening synchronously. FLOWERS: rather showy; corolla broadly cup-shaped to rotate; crown double, of a low ring arising from the corolla tube and 5 distinct, turgid segments (vesicles) arising from the column below each anther, in ours about as long as the gynostegium; anther head more or less elevated on a distinct column, the anther wings flaring outward at the base giving the anther head a truncate-conic form; pollinia pendulous (to slightly divergent) from the translator arms, oblong to oblong-elliptic; stigma head apically rounded and indistinctly 2-lobed. FOLLICLES: striate, the seeds in ours papillate at least on the placental surface. 2n = 22. NOTES: Ca. 35 spp.; in the warmer regions of both hemispheres, preferring more or less arid habitats, and including several leafless succulents of the Old World deserts (Greek: sarx = flesh + stemma = wreath or garland, referring to the fleshy inner crown segments). Holm, R. 1950. Ann. Missouri Bot. Gard. 37: 477-560. REFERENCES: Sundell, Eric. 1994. Asclepiadaceae. J. Ariz. - Nev. Acad. Sci. Volume 27, 169-187.