Cheiridopsis is a genus of approximately 41 species of succulent, perennial flowering plants in the family Aizoaceae (the ice plant or fig-marigold family), order Caryophyllales. All species are native to the semi-arid regions of western Namibia and the Cape Provinces of South Africa, where they thrive in the Namaqualand and adjacent areas under a winter-rainfall climate.
Most species are clump-forming; a few adopt a low shrubby habit. The leaves are borne in opposite pairs and are distinctively triangular in cross-section, rarely flattened, with a surface that is more or less velvety — a feature that readily distinguishes Cheiridopsis from the closely allied genus Argyroderma. Each successive pair of leaves differs from the previous one in form, size, and the degree to which the leaf bases are united. The outer, older pair withers during the dry, hot summer dormancy period and forms a papery, sleeve-like sheath that shelters the emerging inner pair — an elegant adaptation to seasonal drought.
Flowers are solitary and daisy-like, opening during the day in summer. Petals are most commonly yellow, though purple and red forms occur in some species. Cheiridopsis belongs to the subfamily Ruschioideae within Aizoaceae, a group that is especially diverse in the succulent flora of the Greater Cape Floristic Region.
Etymology
The genus name Cheiridopsis derives from the Greek cheiris ("sleeve"), an allusion to the papery sheath that the withered outer leaf pair forms around the next emerging leaf pair during the plant's summer dormancy.
Distribution
Cheiridopsis occurs in the far west of southern Africa, from South Africa's Western Cape Province northward through Namaqualand and into western Namibia. The range is tightly associated with the region's semi-arid, winter-rainfall belt.
Ecology
Species are highly adapted to a very arid, winter-rainfall regime. During the dry, hot summer the outer leaf pair withers and contracts into a protective papery sheath that covers the dormant inner pair, reducing water loss. Growth and flowering occur in the cooler, wetter winter months.
Cultivation
Most species require sharply drained, low-fertility soil and minimal water in summer, matching their winter-rainfall natural habitat. C. peculiaris is more frost-tender and must be grown under glass in temperate climates. Overwatering in summer dormancy is the most common cause of failure in cultivation.
