The Apocynaceae are trees, shrubs or
sometimes herbs, usually with milky sap comprising about 200 genera
and 2,000 species.
- The leaves are simple, usually
opposite and decussate, or whorled; stipules are usually
absent.
- The flowers are bisexual and
actinomorphic or sometimes weakly zygomorphic.
- The calyx is synsepalous and
usually 5-lobed
- The ovary is usually superior,
bicarpellary, and apocarpous, with a common fused style and
stigma.
- Seed: Endospermic, hairy or
winged.
- Pollination: Entomorphilous.
- Habit: Herbs (Catharanthus), shrubs
(Carissa, Nerium), twinners (Vallaris), tree (Alstonia) with
latex.
- Root: A much branched tap root
system