FIG. 15.—CEREUS NYCTICALUS
[C. triangularis] (three-angled); Bot. Mag. 1884.—This plant is easily recognised because of its stout triangular stems, which increase at a rapid rate and bear roots freely; by means of these roots they cling to almost any substance with which they come in contact. There are large examples of it in the Kew collection, where it bears numerous flowers annually, which open in the evening and close at about eight o'clock next morning. The flowers measure 1 ft. in length by about the same in width of cup, and are composed of a whorl of long narrow green sepals, with pale brown points, a cluster of pure white petals, bright yellow stamens, and a large club-like stigma; they appear in autumn. Mexico. This species was cultivated at Hampton Court in 1690.
[C. speciosissimus] (most beautiful).—Although not a night-flowering kind, nor yet a climber, yet this species resembles in habit the above rather than the columnar-stemmed ones. It is certainly the species best adapted for cultivation in small greenhouses or in the windows of dwelling-houses, as it grows quickly, remains healthy under ordinary treatment, is dwarf in habit, and flowers freely—characters which, along with the vivid colours and large size of the blossoms, render it of exceptional value as a garden plant. Its stems are slender, and it may be grown satisfactorily when treated as a wall plant. For its cultivation, the treatment advised for Phyllocactuses will be found suitable. When well grown and flowered it surpasses in brilliancy of colours almost every other plant known. Specimens with thirty stems each 6 ft. high, and bearing from sixty to eighty buds and flowers upon them at one time, may be grown by anyone possessing a warm greenhouse. The stems are three to five angled, spiny, the tufts of spines set in little disks of whitish wool. The flowers are as large as tea saucers, with tubes about 4 in. long, the colour being an intense crimson or violet, so intense and bright as to dazzle the eyes when looked at in bright sunlight. When cut and placed in water they will last three or four days. April and May. Mexico, 1820. "Numberless varieties have been raised from this Cereus, as it seeds freely and crosses readily with other species. Many years ago, Mr. D. Beaton raised scores of seedlings from crosses between this and C. flagelliformis, and has stated that he never found a barren seedling. Much attention was given to these plants about fifty years ago, for Sir E. Antrobus is said to have exhibited specimens with from 200 to 300 flowers each. I have been informed that an extremely large plant of this Cereus, producing hundreds of flowers every season, is grown on the back wall of a vinery at the Grange, Barnet, the residence of Sir Charles Nicholson, Bart." (L. Castle).
THE SEMI-SCANDENT SPECIES.
These are characterised by a thin, drooping or trailing stem, and, though not strictly climbers, they may most fittingly be considered in a group by themselves. Some botanists have made a separate genus for them, viz., Cleistocactus, but for all practical purposes they may be grouped under the above heading, whilst popularly they are known as the Rat's-tail or Whipcord Cactuses. Two of them—viz., C. flagelliformis and C. Mallisoni—are generally grafted on the stem of some erect, slender Cereus or Pereskia, or they may be worked on to the stem of a climbing Cereus, such as C. triangularis, in such a way as to hang from the roof of a house. A large specimen of C. flagelliformis, growing from the climbing stem of C. rostratus, was, for a long time, conspicuous among the Cactuses at Kew, but owing to the decay of the "stock" plant, this fine specimen no longer exists. A large Pereskia, trained along the roof in the Cactus-house at Kew, has recently been grafted with a number of pieces of C. flagelliformis, which in a few years will, no doubt, form a handsome specimen. In the same establishment a specimen of C. Mallisoni is grafted on the stem of another kind, and is very attractive when in flower. C. serpentinus thrives well upon its own roots. For the cultivation of this little group, the instructions given for the climbing and other kinds may be followed.
[C. flagelliformis] (whip-formed).—Stems prostrate, or, when grafted on a tall stem, pendent, ½ in. in diameter, round, with numerous ridges almost hidden by the many clusters of fine bristle-like hairs. Flowers 2 in. long and 1 in. wide; colour bright rosy-red. In some parts of Germany this plant is one of the commonest of window ornaments, and it is so well grown by the peasants there, that the whole window space is completely screened by the numerous long, tail-like stems, 4 ft. or 6 ft. long, which hang from baskets. It is sometimes cultivated by cottagers in England, and we have seen a very fine specimen in a cottager's window in Gunnersbury. Without its pretty bright-coloured flowers, this Cactus has the charm of novelty in the form and habit of its stems, and as it is easily cultivated in a window through which the sun shines during most of the day, it is just the plant to grow for the double purpose of a screen and a curiosity. If planted in baskets, it should be potted in a porous loamy soil, and kept moist in the summer and perfectly dry in winter. Summer. Peru. Introduced 1690.
[C. Mallisoni] ( Mallison's); Bot. Mag. 3822.—This is supposed to be of hybrid origin, a Mr. Mallison having sent it to Dr. Lindley to be named, and stating that he obtained it by fertilising flowers of C. speciosissimus with pollen from C. flagelliformis. Whatever its origin, it is a distinct kind, with stems similar to those of the last-named, but thicker and slightly less spiny, and flowers 4 in. long by 4 in. across the spreading petals, the whole being bright red with a cluster of pale yellow stamens protruding 1 in. beyond the throat. The flowers are produced from the sides of the stems, a few inches from the apex, and as they are borne in abundance and last three or four days each, a large specimen makes a very attractive display for several weeks in the summer. The plant at Kew, a large one, is grafted on the stem of C. Macdonaldiae, which is trained along a rafter, so that the stems of C. Mallisoni hang conspicuously from the roof.
[C. serpentinus] (serpent-like); Fig. 16.—When young, the stems of this plant are erect and stout enough to support themselves; but as they lengthen they fall over and grow along the ground, unless supported by a stake or wire; they have numerous ridges, with clusters of hair-like spines, which are usually purplish. Flowers large, handsome, fragrant; tube 6in, long, green; petals and sepals spreading and forming a star 3 in. in diameter, the petals purplish on the outside, and pinkish-white inside; stamens arranged in a sort of cup 1 in. deep. This plant rarely produces aerial roots. Small specimens are ornamental even when not in flower, the bright green, regularly ridged stem, with its numerous little clusters of fine spines, at the base of which are short tufts of a white woolly substance, being both curious and pretty. It flowers freely every summer. South America, 1814.
FIG. 16.—CEREUS SERPENTINUS