Cotyledonoideae

The Cotyledonoideae are centred in South Africa but extend northward and, in the genus Umbilicus (3.1), through Ethiopia to Europe and Western Asia. The single species of Chiastophyllum, C. oppositi-folium, a popular hardy rock plant with nodding sprays of pale yellow blooms, comes from the Western Caucasus.

Cotyledon (10.8) is really two genera in one, half its 50 species having opposite, persistent leaves and a shrubby habit like Kalanchoe, the other half having spirally arranged deciduous leaves and a more or less caudiciform appearance. Both have relatively large, showy, tubular flowers with parts in fives. There are many hybrids fecorded, but none between species of the two different groups. The flowers of Cotyledon hang down in the manner of bells; those of the closely related Adromischus are held stiffly erect. Adromischus (10.9) is a justly popular genus of dwarf, trouble-free plants that are at home in 7-9cm (3-3!4in) pots and propagate freely from single leaves. They are esteemed for the great variety of leaf forms and markings, some mottled with purple, some silvery and glaucous, and differing in shape often on one branch. A. herrei is a miniature oddity whose leaves are shaped like small lemons, rough and pustulate and deep purplish — something like currants to look at. Although there

Above C 10.8] Cotyledon orbiculata var dinteri. an attractive small variety ot a variable species, with squat, almost white waxy leaves This plant is 14cm (5%in) high.

Below (10 9): Adromischus maculatus with age develops quite a massive caudex. Propagation is easy from single leaves All species ot this genus are happy in small pots

Above(IO. 10) Echeveria leucotricha has flower-like rosettes of leaves covered in silky hairs- an effective means of reflecting the fight and conserving water

are a great many described species in Adromischus, in habitat in South and South West Africa they intergrade. and a future monographer may well prefer to reduce the number drastically.

Echeverioideae

The Echeverioideae are exclusively American. centred in Mexico, and are especially attractive to collectors (2.2). A glasshouse filled with echeverias is uniquely attractive, the banks of rosettes of all colours and sizes looking like a huge floral display. Many border on frost hardiness and are quite well-known outside the ranks of the cactophiles for their use in summer bedding. Floral clocks and similar massed bedding displays at seaside resorts make much use of echeverias. The elegant inflorescences of red to yellow flowers (page 119) last a long time and are popular with flower arrangers. Propagation is easy, by division, from single leaves or even from old flower stalks, which can be rooted and eventually grow. A standard monograph of Echeveria by E. Walther was published posthumously in 1972. It is difficult to make a choice of names from among the 150 species, because all are worth growing, and there are in addition many hybrids, some fantastically ornate.

Dudleya. with 43 species, is a close ally

Above(IO. 10) Echeveria leucotricha has flower-like rosettes of leaves covered in silky hairs- an effective means of reflecting the fight and conserving water

Above (10.12) Sedum hintonii. a collector's piece trom Mexico, is not easy to adapt to cultivation tor long Starvation intensifies the compactness of habit and whiteness ol leaves

Below( 10.13) Sedum sempervivoides mimics a houseleek rosette the first year, but bears a line corymb ol red flowers the second II is a hardy biennial, raised only trom seed

and has beautiful white-powdered foliage (8.6). Graptopetalum, with 11 species, is notable for the dappling of dark spots on the corolla (10.18). In Pachyphytum the leaves are usually thick, smooth and glaucous; P. oviferum ( 10.11) is so named from the egg-shaped leaves. There are about a dozen species, all from Mexico.

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