Crassula cymbiformis was named by Helmut Toelken in the Flora of Southern Africa in 1985 from plants collected by Dave Hardy (1931–1998), succulent horticulturist at the Pretoria National Botanical Garden. Dave collected his plant on the Rankin’s Pass. The Latin epithet cymbiformis, means ‘boat-shaped’, and pertains to the leaves.

Several attempts by the author to locate Crassula cymbiformis on the Rankin’s Pass adjacent to the Kransberg failed. However, on an expedition on 18 March 2003 with SANBI colleagues Andrew Hankey, David Dlamini and Thompson Mushinyalo, the plants were located on the farm Houtboskloof of the Kransberg, which is part of the Marakele National Park. Crassula cymbiformis appears to be an obligatory cliff-dwelling species, and perhaps drifting seeds germinated on the Rankin’s pass where Dave Hardy collected his plants.

Fig. 5. A cluster of Crassula cymbiformis in flower in autumn, growing on a south-facing quarzitic sandstone cliff of the Waterberg, Limpopo Province, South Africa.

Crassula cymbiformis belongs to section Rosulares, which includes the plants that are characterised, as its name implies, by having leaves in tight basal rosettes. The leaves all have the firm bristle-like hairy margin and the elongate inflorescence with a distinct peduncle. Plants vary from the dwarf C. socialis to C. acinaciformis which can be more than 1 m tall when in flower.

Crassula cymbiformis is related to Crassula flanaganii, they both have loosely arranged leaves and thin irregular cilia, but Crassula cymbiformis is a more robust, compact succulent and has thick stems to 10 mm in diameter, and cymbiform leaves.

Fig. 6. Crassula cymbiformis growing in a horizonal crevice on a south-facing quarzitic sandstone cliff face in the Waterberg. Note the dense growth of numerous white lichens, which are an indication of seasonal humidity and fog.