In the list that follows I have briefly described 72 genera and their cultivation, mainly those which are relativelyand obtain. Synonyms are not mentioned except where really necessary. The following abbreviations are used:
T. : Temperature Min. : Minimum
R. : Resting period Max. : Maximum
P. : Propagation W. : Winter
The resting period may vary from species to species, and is only a generalisation; cultivation should never rely on the calendar. Since with few exceptions allcan be readily increased from both and , and offsets where produced, no specific details of are given for these. Adromischus (Crassulaceae) Low-growing plants, sometimes with short , and varying from flat and spoon-shaped to fat and club-shaped or rounded; often nicely mottled, from £ — 4 in. long. Flowers small, in spikes or clusters, pink or white. All are worth growing. Min. W.T., 70 C. (450 F.). P., , cuttings or .
Aeonium (Crassulaceae) Attractive plants making tight rosettes, similar to the hardy Sembervivum. But tender and often with loner branching. The leaves, sometimes toothed or edged with hairs, are less fleshy, and the rosettes are open, bowl-shaped or, as in A. tabulaeforme, quite flat. The small bright , red, pink, white or yellow, are packed into much-branched clusters, often produced only after several years. The rosettes that produce die afterwards. Some (e.g. A. canariense, A. nobile) make large rosettes up to 2 ft. across, and correspondingly large flower-heads. Others (e.g. A. domesticum) make nice little miniature trees. Easy and worth-while to grow, and thrive in rooms. In winter only frost protection is needed but do not exceed 10-° C. (50 F.). P., , very quick from cuttings.
Agave (Agavaceae) Rosette plants, usually with very hard leaves with spines along the edges, often variegated with white, yellow, pink or pale green. The leaves are commonly broadly lanceolate but occasionally very narrow. A trunk is sometimes formed. Some eventually grow to great size. Flowers on upright spikes, often only appearing after many years; individual rosettes die after flowering. Most make attractive pot plants when small. Easy to grow, many needing only frost protection, and resist neglect; useful in tubs in the summer. P., seed, offsets.
Aloe (Liliaceae) Rather dull plants, usually forming rosettes, or sometimes with leaves in two rows, and frequently with long stems. Rosettes similar to agaves, but leaves usually fewer, often toothed. Flowers, sometimes showy, red, orange or yellow, on long stalks. Commonly cultivated is A. variegata, the Partridge Breast Aloe, with stubby dark green leaves with many white marks. Tough, easy plants, good in rooms; frost protection only; plenty of water in summer. P., seed, offsets, sometimes fromcuttings. Repot every year in late summer.
Aporocactus (Cactaceae) The Rat’s-tail, epiphytes with long, trailing, ribbed stems up to 3 ft. or more, around \ in. thick, covered with small spines. Need growing in a basket or do well grafted on a columnar such as Nyctocereus serpentinus or Seleiricereus spp. The pink or red flowers, about 3 in. long, appear in late spring. Best known is A. flagelliformis. Prefer a rich, peaty, lime-free soil, with cow manure and plenty of space. Wet and warm in the growing season. Min. W.T., 10 ° C. (50 ° F.).
Argyroderma (Aizoaceae) Small stemless plants, usually making only one or two pairs of thick leaves, each pair joined at the base; often forming clumps. The leaves are generally rounded outside and flat on the inner faces of the pair, but are sometimes fingerlike (e.g. A. braunsii). Flower freely, in various colours. Min. W.T., 10-° C. (50 F.). R., mainly WM varies with species: all but dry. P., seed. Astrophytum (Cactaceae) The Star Cacti, globular, with four to eight ribs, usually well marked, spineless in A. asterias and A. myr10-stigma, with stiff spines in A. ornatum and papery spines in A. capricorne. The four-ribbed A. myriostigma quadricostata is sometimes called Parson’s Cap. The bodies are covered with tiny white tufts. The flowers are large and yellow. Water with care. Easily grown and very attractive.
Bryophyllum (Crassulaceae) Related toand by some botanists now included in that genus. Tall, bushy plants, often shrubby in nature, making in the leaf-notches or, in B. proliferum, among the flowers, which are quite large, in clusters, appearing usually in autumn or winter. B. crenatwn has oval leaves and red flowers;
B. daigremontianum, the Mexican Hat, has long triangular leaves and yellow or pink flowers; B. iubiflorum has long, thin, cylindrical leaves withat the end, and orange flowers. They make nice room plants, needing rich soil and only slight heat in winter. P., seeds or plantlets; the latter root anywhere!
Carpobrotus (Aizoaceae) C. edulis, the Hottentot Fig, with large white, magenta or yellow flowers and long, thick, triangular leaves, is a plant often naturalised on our south and south-west coasts. Other species are similar. Strong-growing plants, almost hardy, suitable for planting out in frost-free places; not so satisfactory and shy-flowering, in. Very rich soil. P., cuttings best.
Cephalocereus (Cactaceae) Large columnar cacti, usually woolly or hairy, especially at the top, and with spines. The wool and spines only develop well on old plants. The flowers are small. Though there are scores of species, the only one commonly grown is C. senilis, the Old Man. All are rather tricky; water sparingly. Add extra limestone to the. Min. W.T., 7°C. (450 F.).
Cereus (Cactaceae) Large plants with ribbed or angular spines, columnar stems, often bluish. The flowers are large and open at night. Many of the specimens in commerce are hybrids. The most commonly seen species include steely-blue C. chalybaeus, with red and white flowers 7 or 8 in. long; bluish-green
C. jamacaru] and C. peruvia?ius, which has several cristate forms. Good stock for grafting. All species are easilv grown.