the late Mr. Bentham, sunk the genus under Cereus; but
there are sufficiently good characters to justify us in retaining, for
garden purposes, the name Pilocereus for the several distinct plants
mentioned here. The botanist who founded the genus gives the following
general description of its members: Stems tall, erect, thick, simple or
branched, fleshy, ridged; the ridges regular, slightly tubercled, and
placed closely together. Tubercles generally hairy, with bunches of
short spines; the hairs long and white, especially about the apex of the
stem, where they form a dense mass. Flowers on the extreme top of the
matured stems, and arranged in a cluster as in the Melon Cactus, small,
tubular; the petals united at the base, and the stamens attached to the
whole face of the tube thus formed, expanding only at night, and fading
in a few hours. These flowers have a disagreeable odour, not unlike that
of boiled cabbage. Fruit fleshy, round, persistent, usually red when
ripe. The species are natives of tropical America, and are generally
found in rocky gorges or the steep declivities of mountainous regions.

Cultivation.--These plants require distinctly tropical treatment.
During summer, they must have all the sunlight possible, and be supplied
with plenty of water, both at the root and by means of the syringe. Air
should be given on very hot days, but the plants should be encouraged to
make all the growth possible before the approach of winter. In winter,
they may be kept quite dry, and the temperature of the house where they
stand should be maintained at about 60 degs., rising to 65 degs. or
70 degs. in the day. In March, the plants should be repotted into as
small pots as convenient, employing a good, loamy soil and ample
drainage. Should the hairs become soiled or dusty, the stems may be laid
on their sides and then syringed with a mixture of soft soap and warm
water, to be followed by a few syringefuls of pure water; this should
cleanse the hairs and give them the white appearance to which the plants
owe their attractiveness.

SPECIES.

P. Houlletianus (Houllet's); Fig. 56.--Stem robust, glaucous-green;
ridges about eight, broad, prominent, obscurely tubercled; spines in
bundles of nine, radiating, straight, less than 1 in. long, and pale
yellow. Upon the growing part of the stem, the spines are intermingled
with long, white, cottony hairs, often matted together like an unkempt
head; these hairs fall off as the stem mat