Euphorbia is a genus in the family Euphorbiaceae. Consisting of 2008 species, Euphorbia is the fourth largest genus of flowering plants. Succulent species originate mostly from Africa, the Americas and Madagascar. The common name “spurge” derives from the Middle English/Old French espurge (“to purge”), due to the use of the plant’s sap as a medicinal purgative. The plants are annual or perennial herbs, woody shrubs or trees. Smaller Euphorbias make excellent potted plants while larger species are valuable landscaping plants.

Euphorbia horrida commonly known as African Milk Barrel in English and Noorsdoring, Regopnoors or Regopnoorsdoring in Afrikaans is a South African endemic succulent found exclusively in the Eastern Cape and Western Cape Provinces. Though it is not a cactus it looks like 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, it has blue-green, heavily-ridged spiny stems carrying solitary green flowers in summer. It develops new shoots laterally at the base of the plant, often forming roots and thus a successful means of propagation. The Latin specific epithet horrida means with many prickles.