See discussion under ISI 2006-18. HBG 89498, seedlings from controlled pollination of Röösli & Hoffmann 5800, plants coll. Nov. 23, 2000, E of Falaise d’Ankarana, Madagascar, in forest on tsingy limestone. $8.50.
Published in the Cactus and Succulent Journal, Vol. 78 (2), March - April, 2006