Euphorbia horrida

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, 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, or as a houseplant on a sunny windowsill.
It develops new shoots laterally at the base of the plant offset, often forming roots and thus a successful means of propagation.
The Latin specific epithet horrida means "with many prickles".
This plant has gained the Royal Horticultural Society's Award of Garden Merit.