African milk barrel

Euphorbia horrida, the African milk barrel, is a species of flowering plant in the family Euphorbiaceae, native to South Africa. It is a cactus-like shrub showing remarkable similarities to the true cacti of the New World, and thus an example of convergent evolution. Growing to 1.5 m (4 ft 11 in), it has blue-green, heavily-ridged spiny stems carrying solitary green flowers in summer. In temperate regions it must be grown in heated conditions under glass.