Rock Barrelwort

Euphorbia heptagona forms dense clusters of small succulent branches. Each branch typically has four ridges, each with a line of long spines. Young spines are often red or yellow, darkening to black as they mature. Like all Euphorbia species, Euphorbia heptagona exudes toxic white latex when damaged. Euphorbia heptagona closely resembles many cacti, but this resemblance is due to convergent evolution. Euphorbias are not closely related to cacti. Tests on the plant have identified the presence of flavonoids, alkaloids, tannins, glycosides, anthraquinones, triterpenoids, and phytosterols.

Native to South Africa, Euphorbia heptagona commonly grows in the Eastern Cape and Karoo regions. It grows best in well-drained soil and with direct sunlight.