(Greek, krupto, conceal, and stego, cover; referring to the 5-scaled crown in the corolla tube, which is not exposed to view. Asclepiadaceae. A genus of only two species of tropical climbers one from tropical Africa and one from Madagascar. The juice of C. grandiflora, when exposed to the sunshine, produces caoutchouc. The plant is cultivated in India for this purpose. It is rarely cultivated in Old World greenhouses for ornament. It is said to be of easy culture in a warm house and propagated by cuttings.