This is one of a group of shrubby to arborescent coralliform euphorbias—a reference to their coral-like growth. Included is the common E. tirucali and the thicker-branched E. oncoclada native to SW Madagascar but which this northerly species resembles. This possibly new species forms smaller specimens on the lean, sharp tsingy limestone of its habitat. HBG 97494, Röösli & Hoffmann 5405, seeds collected Dec. 26, 2005, at the dramatic limestone formations called Windsor Castle, near the northern tip of Madagascar. $7.
Published in the Cactus and Succulent Journal, Vol. 80 (2), March - April, 2008