Apocynaceae (, from Apocynum, literally "away-dog" in Greek, i.e. "[that which takes] away [the life of a] dog") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison. Notable members of the family include oleander, dogbanes, milkweeds, wax plants and periwinkles. The family is native to the European, Asian, African, Australian, and American tropics or subtropics, with some temperate members as well. The former family Asclepiadaceae (now known as Asclepiadoideae) is considered a subfamily of Apocynaceae and contains 348 genera. A list of Apocynaceae genera may be found here.
Many species are tall trees found in tropical forests, but some grow in tropical dry (xeric) environments. Perennial herbs also occur in temperate zones. Many of these plants have milky latex, and many species are poisonous if ingested, the family being rich in genera containing alkaloids and cardiac glycosides, those containing the latter often finding use as arrow poisons. Some genera of Apocynaceae, such as Adenium, bleed clear sap without latex when damaged, and others, such as Pachypodium, have milky latex apart from their sap.
Description
Alstonia scholaris, arrangement of leaves
The dogbane family is morphologically diverse, with the highest diversity of forms in tropical and subtropical regions, and includes annual plants, perennial herbs, stem succulents, woody shrubs, trees, or vines. Most exude a milky latex when cut.
Leaves are simple. They may appear one at a time (singly) with each occurrence on alternating sides of the stem, but usually occur in pairs (and rarely in whorls). When paired, they occur on opposite sides of the stem (opposite), with each pair occurring at an angle rotated 90° to the pair below it (decussate).
There is no stipule (a small leaf-like structure at the base of the leaf stem), or stipules are small and sometimes finger-like....
