This is a slender and graceful representative of the Didiereaceae, a family of just 11 thorn-forest species (see ISI 2006-17) native to Madagascar. A. humbertii has slender stems less than half the diameter of the more common A. procera but lined with similar slightly fleshy obovate vertically oriented bright green leaves. The leaves just described for these two species are produced secondarily, and repeatedly with recurring wet seasons. Short-lived primary leaves are produced only on new growth and are more slender, acute and oriented horizontally. In the landscaped bed in our Desert Garden Conservatory A. humbertii has grown rapidly with upright branches that soon arch with a wild sort of grace. Our specimen has been pruned to keep it from becoming too dense and to maintain an attractive shape. Rooted cuts of HBG 69290, UCBG 53.350, a plant collected by M. Ursch at Antanimora, near the dry southern tip of Madagascar. $6.