Usually seen in cultivation as simply M. ritchiei, this subspecies is quite distinct from the typical solitary, columnar form of subsp. ritchiei. Subspecies nyambense is a dwarf plant that branches above ground to form compact clusters. The tubercles are shorter and rounded and arranged in tight spirals. Stem tips are ornamented many months of the year with delightful orangish-pink cyathia. Leaves, when present, are glabrous rather than puberulous. Current taxonomy places Monadenium under Euphorbia to avoid the large volume of name changing that would be required to split out similar distinctive groups within this massive genus. Nevertheless, most growers readily recognize the single-glanded cyathia with their hooded appendages that characterize the group in the strict sense. This is one of two geographical variants described by Susan Carter: subsp. marsabitense from near Marsabit in the North Eastern Province of Kenya and subsp. nyambense from Lagadema Hill in the Meru District some 250 km to the south. HBG 126030, $7.
Published in the Cactus and Succulent Journal, Vol. 88 (3), May-June, 2016