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 pentagona is a South African endemic species from the Eastern Cape Province. Euphorbia pentagona is a medium-green Euphorbia; starts off as having a pentagonal prism shape where each vertex is extruded outwards, and each side is a mild concavity, along the height of the euphorb. Spines, red in colour when fresh, exit the body along each extrusion at equal intervals. As the spines age, they tend to lose their colour. The cross-sectional polygonal shape can gain extra vertexes as new branches grow from the sides. Often branches grow from where a spine once was, or should have been.