C. Berlandieri (Berlandier’s); Fig. 17.—­A distinct and beautiful plant, of dwarf, creeping habit, forming a tuft of short branchlets springing from the main procumbent stems, none of which exceed 6 in. in length by 3/4 in. in thickness.  They are almost round when old, the younger ones being slightly angled, and bearing, along the ridges, little tubercles, crowned with short spines.  Even old stems are very soft and watery, and, on this account, it is necessary for the safety of the plant, in winter, that it should be kept absolutely dry.  The flowers are produced on the young upright stems, and they are as much as 4 in. across.  They are composed of a regular ring of strap-shaped, bright purple petals, springing from the erect bristly tube, and in the centre a disk-like cluster of rose-coloured stamens, the stigma standing well above them.  In form the flowers are not unlike some of the Sunflowers or Mutisia decurrens.  They are developed in summer, and on well-grown plants the display of blossom is exceptionally fine.  This species is sometimes known as C. repens and C. Deppii.  It is a native of South Texas and Mexico, where it is found growing in sandy or gravelly soils, on dry, sunny hill-sides.  It should be grown in a cool greenhouse or frame, in a position where it would get plenty of sunshine to ripen its growth and induce it to flower.  In winter it should be placed close to the glass, where the sun can shine full on it, and where it will be safe from frost.  It will not thrive if wintered in a warm house.  In April, it should be examined, repotted if the soil is sour, and kept watered as growth commences.

[Illustration:  Fig. 17.—­Cereus berlandieri.]

C. Blankii (Blank’s); Fig. 18.—­This is very similar to the C. Berlandieri in habit and stem characters, differing only in having longer, broader, less spreading petals, a club-shaped stigma, and in the colour, which is a deep rose, flushed in the throat with crimson.  A comparison of the figures here given will show the differences better than any description.  C. Blankii comes from Mexico at high elevations, and thrives under cultivation with the same treatment as the preceding.  It is very common in Continental gardens, where it is grown out-of-doors, being protected from cold in winter by a handlight and straw.  It flowers in summer.

[Illustration:  Fig. 18.—­Cereus Blankii.]

C. caerulescens (blue-stemmed); Bot.  Mag. 3922.—­An erect-growing, tall Cactus, rarely branching unless made to do so by cutting off the top of the stem; furrows and ridges about eight, the ridges prominent, waved, and bearing tufts of blackish wool, in which are set about a dozen black spines, 1/2 in. long; the stem when young and in good health is bluish in colour.  Flowers springing from the ridges, about 8 in. long, the tube covered with reddish-grey scales, which pass upwards into the sepals; petals spreading, white, the margins toothed, and forming a spreading