Sarcostemma is a group of about 40 species of climbing vines and sub-shrubs with leafless or leafy photosynthetic stems. Leaves where present are opposite and heart-shaped to lanceolate. Umbels of small flowers arise from leaf nodes.
Taxonomy of this group is controversial. The genus Sarcostemma as originally constituted was widely distributed throughout the sub-tropical and tropical Old World in Africa, India and Malaysia. Recently Sarcostemma was reduced to a synonym of Cynachum and many species moved to other genera. Sarcostemma viminale is very common in southern Africa. Similar New World species are regarded as Funastrum in some taxonomic treatments, but may be seen assigned to either genus.
The leafy tropical American genera Philibertia and Vincetoxicum have been included under Sarcostemma, but are currently recognised in their own right.
Several species in this group are listed as invasive weeds and are best cultivated in pots with a climbing frame, where they can be kept under control. The milky sap is toxic and Sarcostemma australe (Caustic Vine) blisters skin on contact. Some species may contain substances of medicinal value.
A group of about 16 species climbing vines with photosynthetic stems, native to the tropical and sub-tropical Americas. Roots are fleshy rhyzomes. The soft leaves and other parts are often slightly hairy.
Funastrum cynanchoides (Decaisne) Schlechter 1914 (Climbing Milkweed)
Syn. Sarcostemma cynanchoides Decaisne 1844
Widely-distributed across the Southern USA from Florida to California, commonly twining through shrubs, fences and other supports.
The greenish-white to pink petals are fringed with white hairs but the stems and lanceolate to heart-shaped leaves are smooth. Flowers are followed by pairs of pods full of seeds with silken parachutes.
This plant is attractive to bees, butterflies and birds but may be an invasive weed in some areas. Photographed in the Desert Botanical Garden, Phoenix.