SUCCULENT PLANTS 
147 
Cultivation. 
Although they are capable of withstanding — and do, in nature, with- 
stand — extreme and continued drought, it is not advisable in cultiva- 
tion to attempt to imitate Nature’s treatment too 
closely. Except during the three ' dullest months, when 
water may be almost entirely withheld, these plants should be watered 
regularly. But it is most important that there should be perfect 
drainage at the root. Nor should the atmosphere of the house in 
which they grow be kept unusually dry. The old idea that these 
plants need extremely arid conditions is no longer held. Whilst 
admitting that they will tolerate them, it is now perceived that treat- 
ment approximating that of ordinary greenhouse plants is in the 
main suitable for them, especially in summer. Watering need not, 
of course, be so frequent, and artificial shading should be entirely dis- 
pensed with. For many years a few plants too tall for the Cactus 
House have thriven well in the moisture of the large Palm House. 
Whilst the most noticeable features of the plants in this house 
are their fantastic forms and their forbidding array of spines, many 
~ . of them produce flowers of singular beauty. This is 
Cactuses. . ® J . 
especially true of the cactus family, such as the species 
of Phyllocactus, Epiphyllum, and Cereus. To this last genus also 
belong those remarkable species whose flowers open towards night- 
fall, blossom throughout the night, and fade the next morning. This 
genus, Cereus, is on the whole, perhaps, the most remarkable of the 
family of cactuses. The plants frequently take the form of one or a 
cluster of tall, erect, slender, and excessively spiny columns, each no 
thicker at the base than near the top, with fluted or angled sides and 
no leaves. Sometimes the stems are prostrate, sprawling snake-like 
over the ground ; sometimes considerably thicker at the top than 
at the base, and of a shape suggesting a giant’s bludgeon. One of 
the most famous is Cereus senilis, the Old Man cactus, the upper 
part, or head, of which is covered with a shock of grey, wiry hairs. 
The plants grow slowly, and some of those here, but a few feet high, 
are older than many large forest trees. 
Nearly allied to Cereus are Echinocactus and Melocactus, the 
species of which, however, are shorter, thicker, or almost globular in 
form. They are even more formidably armed, some being furnished 
with hooked spines like fish-hooks, others merely curved, and some 
straight — all, however, rigid and hard as spikes of steel. It was a 
species of Echinocactus ( E . Visnaga), nine feet high, three feet in 
