Asclepiadoideae

Asclepiadoideae is a subfamily of flowering plants in the family Apocynaceae (the dogbane family). It was formerly recognized as the separate family Asclepiadaceae, but molecular studies place it within Apocynaceae. The subfamily encompasses a diverse assemblage of herbaceous plants, shrubs, and many succulent genera, including economically and horticulturally important groups.

Typical features include opposite or whorled leaves with milky latex, and flowers that are often elaborate with a tubular corolla and a central corona. The flowers commonly possess pollinia, a specialized pollination mechanism that couples with certain insects, notably hawkmoths in many milkweed relatives. Fruits are usually paired follicles bearing numerous seeds with tufts of hair for wind dispersal. The plants often contain cardiac glycosides and other toxins.

Distribution and genera: The group has a wide distribution in tropical and subtropical regions, with representatives in Africa, Asia, the Americas, and parts of Europe. Notable genera include Asclepias (milkweeds), Calotropis, Cynanchum, Vincetoxicum, Dischidia, Hoya, and the succulent stapeliads such as Stapelia, Orbea, Caralluma, and Huernia.

Ecology and uses: Several species are cultivated as ornamentals, houseplants, or in gardens for their distinctive flowers and, in some cases, drought tolerance. Dischidia and Hoya are popular as tropical ornamentals; stapeliads are prized by collectors. Ecologically, Asclepiadoideae species often play roles as larval host plants (e.g., Asclepias for monarch butterflies) or as specialized pollinator resources. Toxic compounds in many species have been studied for their pharmacological properties, though some are hazardous if ingested.