Cotyledon woodii subsp. cremnophila was named by the author in the magazine Haseltonia, the Yearbook of the Cactus and Succulent Society of America (Van Jaarsveld 2015). As part of the author’s research on succulent obligatory cremnophytes, confined to southern African cliffs, many of the greater river drainage systems were investigated, including the Kei River. The species name cremnophila pertains to its sheer cliff face habitat, kremnos meaning ‘cliff’ and philos, ‘to love’. This plant was first brought to my attention by Cameron & Rhoda McMaster when they brought a specimen to Kirstenbosch which they had collected on the sheer rock faces along the Kei River in the Eastern Cape. At first glance it appeared to be Cotyledon woodii because of its inflorescence being reduced to a solitary flower, as well as its woody nature. On subsequent expeditions, the first to the Kei Bolo in March 2003, and later by rubber canoe to the Kei River in April 2012 the plant was also observed by the author and could be properly investigated and its status and distribution determined. This plant was grown at Kirstenbosch and later at Babylonstoren Farm, together with typical Cotyledon woodii subsp. woodii forms, but it soon became apparent that its size and habit remain constant, therefore warranting subspecific status. The plants keep their low-growing, rock-hugging characteristics, reaching only about to 15 cm high. The very succulent leaves on the branches, often become smaller towards the ends of the branches, somewhat pyramidal, and the margin of the leaves become dark maroon. The internodes are also shorter, only 8 mm long.

Fig. 5. Cotyledon  woodii subsp. cremnophila in habitat on cliffs adjacent to the Kei River, sharing its habitat with Gasteria excelsa, Caputia scaposa and Adromischus liebenbergii subsp. orientalis.

Cotyledon woodii subsp. cremnophila belongs to a group of small-leaved cotyledons. Cotyledon woodii subsp. woodii is widespread, succulent-leaved, erect, much branched woody shrub, to just over a 1 m high, bearing flatter leaves, and commonly encountered in Albany Thicket vegetation, from Ladismith in the Western Cape to the dry river valleys of the Eastern Cape. Cotyledon woodii subsp. cremnophila is also related to Cotyledon pendens, which is only known from the Mbashe River system north-east of the Kei River. They can be confused, however the leaves are more grey and flowers of C. pendens are somewhat smaller and are usually not solitary, and the plants soon become pendent. C. woodii subsp. cremnophila remains a shrublet. It is also related to Cotyledon gloeophylla, a much branched shrub, like C. woodii subsp. woodii, from the eastern Baviaanskloof which has solitary flowers. This species, however, is easily distinguished by its sticky, green leaves.