Family Apocynaceae, of the
Dogbanes have milky, often poisonous juice and usually clustered, showy flowers. Garden ornamentals include periwinkle , oleander , yellow oleander ( Thevetia ), frangipani , Natal plum ( Carissa ), and crepe jasmine ( Tabernaemontana coronaria ). Some species are African {{link=succulent">succulents . Arrow poisons are obtained from many dogbanes, and the poisonous alkaloids of some species are used in medicines.