Euphorbiaceae
A genus comprising about 600 species of stove, greenhouse, or hardy, trees, shrubs, and herbs. The flowers are unisexual, collected into heads; these flower-heads are placed in umbels variously branched, or aggregated into clusters round the top of the stem. Only a very few plants of this genus are worth growing for horticultural purposes. The few hardy species of ornamental value make excellent border plants, and are fit subjects for naturalising on rocky, somewhat dry situations. These may be increased by cuttings, or by division. Two largely grown stove species, that are among the best and most showy of winter-flowering plants, are E. fulgens and E. pulcherrima (the latter is better known under the name of Poinsettia pulcherrima). Another, which is frequently represented in gardens by one or more plants, is E. splendens. The last is nearly always, more or less, in flower; and, although very ornamental, is not of much use, except to remain in the stove. Slow-growing Euphorbias, which are kept for the sake of their addition to a collection of succulent plants, do not require much water, nor a rich soil to grow in. Sandy loam and crushed pieces of brick, in nearly equal proportions, form a suitable compost. E. fulgens is a somewhat slender-growing plant, and is frequently found rather difficult to establish. It succeeds well planted out in the warmest part of a stove, and trained up the back wall or on the roof. It has also been found to grow and flower profusely in a house with Pines, the moisture in summer and drier heat in winter, suiting admirably. It is very impatient of root disturbance, and will not bear sudden changes of temperature without losing its leaves. For culture in pots, young plants may be raised annually. Cuttings 3in. long are best; they should be inserted about June, three in a small pot, and kept close in a warm propagating frame until rooted. These may be afterwards kept growing in heat, and transferred bodily into larger pots, without disturbing the roots. If treated in this way, they need not be stopped, and the single shoots will consequently be much stronger. The plants will not bear cold at any time, but will succeed in frames during the latter part of summer. The flowers are small, produced all along the upper part of the shoots in winter, so that the ripening of the latter by exposure to sun, is important. If kept a little cooler when in flower, they last a long time in beauty, and may be used for cutting, although the leaves frequently droop very quickly. When flowering is over, the plants should be kept quite dry and allowed to rest for a period of three or four months. As is the case with nearly all the species, the beauty of E. pulcherrima does not reside so much in the flowers as in the bracts with which they are surrounded. The system of culture is much the same as with the species already described, but varies in some respects, as the plants are much stronger-growing. Any old ones that have been resting should be introduced to heat about the beginning of June, and, if kept watered, will soon supply plenty of cuttings. These are best inserted singly in small pots, without crocks, in order to preserve the roots afterwards. The best summer quarters is on a spent hotbed, where the tops can be kept near the glass at all times, being lowered, as becomes necessary, by the removal of the manure underneath. It is advisable to put in several batches of cuttings successionally, as plants of various heights may then be obtained. The general plan is to grow on young ones annually, without stopping, the object being to produce a large terminal head of bracts on each. The old plants may also be grown if desired. They will not bear exposure to a low temperature in autumn, the result being invariably the loss of either the roots or leaves. When the bracts appear, more heat and some manure water may be applied, to expand them, and the plants should afterwards be kept a little cooler, to prolong the season in which they remain attractive. E. pulcherrima succeeds best in a soil composed of one-half turfy loam, the remainder being equal parts of dried cow-manure and leaf soil. Pots 5in. to 7in. in diameter are suitable for single plants to flower in. Retaining the foliage in good condition throughout the season, is an indication of good culture, and one of the main provisions for securing the full development of the flower-heads. Sudden changes of temperature in either direction must be avoided, and the plants exposed to plenty of light and full sunshine, except when it is very strong, in summer. After flowering, they should be kept quite dry, in a warm place, to supply cuttings the next year.
E. atropurpurea (dark-purple). fl. (=bracts) deep red-purple, or blood-coloured, large, broadly oblong, obtuse, combined at the base; involucre small, cup-shaped, red, with four retuse, fleshy yellow-green glands at the margin. March. l. numerous, lanceolate, tapering at the base, obtuse, pale glaucous-green, patent or drooping. h. 3ft. to 6ft. Teneriffe. A very pretty greenhouse species. (B. M. 3321.) E. Cyparissias (Cypress Spurge). fl. yellow, umbellate; involucral leaves somewhat cordate, about twenty in number, often yellow. Spring. l. linear, quite entire, somewhat crowded. h. 1ft. to 2ft. Europe (naturalised in Britain). Hardy. (Sy. En. B. 1262.) E. fulgens (shining). fl., bracts bright orange-scarlet, axillary, forming long wreaths. l. bright green, lanceolate. h. 4ft. Mexico, 1836. Stove. One of the handsomest of winter-flowering plants. SYN. E. jacquiniaeflora. (B. M. 3673.) E. jacquiniaeflora (Jacquinia-flowered). Synonymous with E. fulgens. E. meloformis (Melon-like). fl. greenish. Plant unarmed, with many angles. h. 6in. to 9in. Cape of Good Hope, 1774. Stove or warm greenhouse. E. Monteiri (Monteiro's). fl. green; involucre sub-regular campanulate, turbinate, or hemispherical. June. l. fleshy, glabrous, narrow, spathulate. Branchlets floriferous. h. 2ft. to 6ft. Bahia, 1864. A very remarkable species, on account of the curious successive productions of the staminate flowers. Stove. (B. M. 5534.) E. Myrsinites (Myrsinites). fl. yellow, in an umbel of from five to nine rays, surrounded by an involucre of ovate, sharp leaflets. Summer. l. fleshy, concave, light green, sessile. South Europe. A very ornamental hardy prostrate species. (S. F. G. 471.) E. pulcherrima (pretty). fl. greenish-yellow, subtended by large vermilion bracts, small. Winter. l. ovate-elliptical, sub-acute, petioled. h. 2ft. to 6ft. Mexico, 1834. Shrub. SYN. Poinsettia pulcherrima. (B. M. 3493.) There is a variety of this with creamy-white bracts, and another (E. p. plenissima) with double series of bracts (G. C. n. s., v. 17).
E. splendens (splendid). fl., bracts bright red, waxy, clustered. l. bright green, texture thin, rather small. Stems dark-coloured, closely set with long, stout, sharp thorns. h. 4ft. Bourbon, 1826. A handsome stove species, with sturdy branching habit.
Several hardy species of Euphorbia, now almost lost to our gardens, are well worth culture. Among these may be mentioned aleppica, with dense terminal heads of flowers, and crowded linear-oblong leaves; Characias, with the flower-stalks equal in length and verticillate; pilosa, with dense terminal tufts of greenish-yellow flower-heads, and linear-oblong leaves. Among the species indigenous to this country, amygdaloides and Paralias are well worthy a place in the wild garden, and in the margins of shrubberies. The following is a list of species sometimes grown in company with succulent plants: abyssinica, anacantha, antiquorum, aphylla, canariensis, capensis, Caput-Medusae, erosa, globosa, grandicornis, grandidens, hystrix, imbricata, mammillaris, mauritanica, neriifolia, officinarum, pendula, resinifera, scolopendria, serpens, squarrosa, trigona, xylophylloides.