n diameter, sulphur-yellow, tinged with purple, produced in
August and September. Fruit 21/2 in. long and 1 in. thick, covered with
cushions of bristles and spines. A native of Mexico, on dry, sandy
soils, where its prostrate stems, clothed with powerful spines, form a
hiding-place for the small animals, snakes, &c. Stove or warm greenhouse
treatment is best for this species.

O. Engelmanni (Engelmann's).--A stout, coarse-looking plant, 6 ft. high,
with woody stems and large, flat, green joints, 1 ft. long and 9 in. in
diameter. Cushions 11/2 in. apart, composed of coarse bristles, and one or
two spines over 1 in. long, and pointing downwards. Flowers 3 in. in
diameter, yellow, produced in May and June. Fruit nearly round, 2 in.
long, purplish both in rind and pulp, the latter rather nauseous to the
taste. Mexico. This is a greenhouse plant which grows freely and flowers
annually under cultivation. It is very similar to O. monacantha, a much
better known species. According to American botanists, it is probably
the most widely spread of the whole Cactus tribe.

O. Ficus-indica (Indian Fig); Fig. 80.--Branches erect, 8 ft. to 12 ft.
high; joints flat, oval or obovate, about 1 ft. long by 3 in. in width,
and 1 in. in thickness. Stems hard and woody with age. Cushions 11/2 in.
apart, composed of short, yellowish bristles, and very rarely one spine.
Flowers 3 in. to 4 in. across, sulphur-yellow, produced all through the
summer. Fruit 3 in. to 4 in. long, pear-shaped, covered with tufts of
bristles, white, yellow, or red when ripe. It is a native of Central
America, whence it was introduced about 300 years ago. It is now widely
spread, in tropical and temperate regions all over the world. In many
parts it is cultivated for the sake of its fruits, which in some of our
colonies are used for dessert. In England it must be protected from damp
and cold; it is, therefore, best cultivated in a sunny greenhouse during
winter, and placed outside in a position exposed to full sunshine all
summer. Tenore, an Italian botanist, named this species O. vulgaris, and
this mistake has led others to consider the North American O. vulgaris
(true) and O. Ficus-indica as one and the same species.

[Illustration: FIG. 80. FRUITING BRANCH OF OPUNTIA FICUS-INDICA.]

O. filipendula (hanging filaments); Fig. 81.--Stems prostrate, about
1 ft. high, spreading; joints flat, round or oval, about 3 in. long, often
less, milky-green in colour. Cushions 1/2