Cotyledon orbiculata and its cultivars

C otyledon orbiculata was one of the first South African succulents to come to the attention of European explorers in the Cape. It gained the unflattering name of “Pig’s Ears” in addition to at least a dozen native names over the wide area in which it occurs. Its history from 1624 onwards has been well-recorded by van Jaarsveld and Koutnik1 so will be only briefly mentioned here. It probably reached the UK by 1690, the introduction being credited to the Earl of Portland or a Mr Bentink. There were doubtless later introductions, and ease of propagation from cuttings or single leaves soon led to the spread of different forms (morphs) to wherever succulents were favored as ornamentals. By 1789 Williams Aiton, while cataloging the plants grown at Kew2, recognized four variants differing in habit and leaf shape, and Candolle in 1828 added a fifth3 and gave them Latinized names. Aiton, however, had given his four English names: Ovate-leaved Navelwort ( = variety ovata), Oblongleaved Navelwort ( = variety oblonga), Branching Navelwort ( = variety ramosa), and Round-leaved Navelwort ( = variety rotundifolia). These are vernacular (rather than cultivar) names translated direct from the Latin, and we are not obliged to retain them as cultivar names (ICNCP Rec. 26 A)4. “Navelwort” is one common name for Umbilicus rupestris, the European native Wall Pennywort, then classified as Cotyledon umbilicus. Toelken5,6 revived the genus Cotyledon and accepted five varieties under C. orbiculata based on field surveys, floral structures and other features, rather than the all-too-variable characters given heed by earlier workers. Their names were rightly reduced to synonymy. He also provided a pictorial map showing the variability of the species from region to region in South Africa. Toelken’s varieties can be separately keyed out as follows