, flat, cartilaginous, whitish, and curving
downwards. On healthy large examples these spines are 2 in. long, and
nearly 1/4 in. wide at the base. Flowers and fruit not known. Native of
Mendoza (La Plata). This little plant requires to be cultivated in a
warm greenhouse or stove, but it grows very slowly. It is certainly a
most interesting Cactus; examples of it may be seen at Kew, where there
is a plant which, although over ten years old, is only 4 in. high. Syns.
O. platyacantha and Cereus syringacanthus.

O. Dillenii (Dillenius'); Fig. 79.--An erect-growing, robust species,
attaining a height of 15 ft., with flattened, ovate joints, about 5 in.
long by 3 in. broad. Cushions composed of short, white, hair-like
bristles, and numerous long, stout, yellow spines. Flowers yellow,
tinged with red, 4 in. in diameter, freely produced on the ends of the
youngest joints all summer. Fruits similar to those of O. Ficus-indica.
A native of the West Indies, now naturalised in all warmer parts of the
world. In India it is so plentiful and widespread that Roxburgh, an
Indian botanist, said it was a native. In India, its fruits are eaten by
the poor natives, and it is often planted as a hedge. It is also a great
pest in the open lands of that country, and large sums are annually
expended in cutting it down and burying it. This species, which requires
warm greenhouse treatment, is also employed in the cultivation of
cochineal.

[Illustration: FIG. 79. OPUNTIA DILLENII.]

O. echinocarpa (spiny-fruited).--A low, straggling shrub, not exceeding
11/2 ft. in height. Joints cylindrical, from 1 in. to 3 in. long, less than
1 in. thick. Cushions of rather coarse bristles and numerous spines, from
1/2 in. to 1 in. in length. Flowers 2 in. in diameter, yellow, produced in
summer. Fruit short, depressed, almost saucer-shaped, and bearing spines
nearly 1 in. long. A native of Colorado, &c. It requires stove treatment.
The variety major has stems 4 ft. high, joints 8 in. to 10 in. long, and
long, sheathed spines. This species is closely related to O. Bigelovii
and O. Davisii.

O. Emoryi (Emory's).--A prostrate, spreading plant, less than 11/2 ft.
high. Joints cylindrical, curved, 4 in. long, 11/2 in. thick. Tubercles very
prominent, longitudinally attached to the stem, the apices crowned with
pea-shaped cushions of short bristles, and numerous radiating spines,
some of which are fully 2 in. long, very strong and needle-like. Flowers
21/2 in. i