The dogbane family's name literally means away, dog
Apocynaceae takes its name from Greek words meaning away and dog, because some of its plants served as dog poison. The same family gives us frangipani, milkweed and oleander, arrow poisons, heart drugs and a cancer medicine from the Madagascar periwinkle. Many bleed milky latex when cut.
Around 5,100 species, counted in 2012, make up the dogbane family, and a 2014 classification sorted them into 366 genera. They include trees, shrubs, vines, herbs and stem succulents spread across the tropics and subtropics of every inhabited continent, with some temperate outliers. Milkweeds, once a family of their own called Asclepiadaceae, now form a subfamily. Leaves are simple and usually paired, each pair turned at right angles to the one below.
The flowers are intricate: five petals fused into a tube, a swollen style head, and pollen carried in foam. Fruits range from berries and drupes to paired pods, and seeds often bear wings or tufts of silky hair for the wind. Habitats vary enormously. In the swamp forests of Indomalaya, Alstonia and Dyera grow into buttressed giants up to 80 metres tall; Central America has the sweetly scented frangipani; the Mediterranean has oleander; southern Africa and Madagascar host the succulent Pachypodium. In temperate Europe away from the Mediterranean, only Vinca and Vincetoxicum occur naturally. North America's Apocynum cannabinum was a traditional fibre source.
Chemistry is the family's defining trait. Many members are rich in alkaloids and cardiac glycosides, which affect the heart; plants loaded with the latter were used to tip arrows and cause many accidental and sometimes fatal poisonings. Oleander, Cerbera and Strophanthus belong to this dangerous set.
Those same compounds feed medicine. Indian snakeroot, Rauvolfia serpentina, yields reserpine, used against high blood pressure and psychosis, though side effects restrict it. Catharanthus roseus supplies alkaloids for cancer treatment. Tabernanthe iboga contains ibogaine, a psychedelic studied for addiction but toxic to heart and nerves. Several genera also feed the caterpillars of the Queen butterfly.
Source: Apocynaceae
