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6. What plants are related to Adromischus?

The genus Adromischus is part of the family Crassulaceae, one of very few families that consists almost entirely of succulent plants. For a recent technical view about how the Crassulaceae fits with other families as part of the Saxifragales and other higher orders of seed plant classification, visit the Angiosperm Phylogeny Website by P. F. Stevens.

Traditionally, the Crassulaceae was split into six subfamilies (Berger 1930). Recent molecular studies reveal seven clades (Mark Mort et al. in Am. J. Bot. 88:1 (2001) p. 76-91). The Southern African genera Cotyledon and Tylecodon are most closely related to Adromischus, with the Eastern African and Madagascan genera Bryophyllum, Kalanchoe and Kitchingia completing the clade.

Historically, the genus Cotyledon Linnaeus (1753) was described first. Adromischus Lemaire (1852) was not widely used for a long time and the earlier species were described as Cotyledon. Included within Adromischus were a few species of Tylecodon Tölken (1978), before it was separated.

Adromischus with 29 described species, contains squat to spreading, dwarf to small subshrubs with perennial, alternate leaves and a rarely-branched spike-like inflorescence with erect, spreading flowers (except pendant in A. phillipsiae). Commonly called "Kleinplakkies" or "Bontplakkies" in Afrikaans.

The widespread Cotyledon orbiculata, about 18" (45 cm.) high in the Little Karoo, W. Ladismith.

Cotyledon now with only 11 species, contains small, woody shrubs with opposite (or tri-merous), perennial leaves and a branched inflorescence with pendent flowers when open. Their centre of diversity is in the Eastern Cape but one species (C. barbeyi) has a distribution from South Africa to East Africa. Generally, they are rather large for pot cultivation where heating is needed. Commonly called "Plakkies" in Afrikaans and some are known to be poisonous to livestock..

Tylecodon longipes, in a 2" (5 cm.) pot, from the TL, Kloof of Caves, Richtersveld.
It flowers in the summer after the leaves have shrivelled.

Tylecodon with about 45 species, contains pachycaul, dwarf geophytes to shrubs (to scramblers) with deciduous, alternate leaves and a branched inflorescence with usually erect flowers when open. All are from Namibia and South Africa, with a centre of diversity in Namaqualand. New species are still being found. They are very suitable for pot cultivation, but slow to propagate.

Full information about Cotyledons and Tylecodons can be found in the book by van Jaarsveld & Koutnik.