ge, nearly 1/2 in. long and wide. This handsome South American
species was the subject of an interesting communication to the
Gardeners' Chronicle, in 1884, from Dr. Engelmann. It had previously
been known as a Pereskia from the fact of its leaves being persistent
and very large. In its leaves, flowers, and seeds, O. subulata is one of
the most interesting of the genus. It is easily grown in a warm
greenhouse, and deserves a place in all collections of Cactuses.

O. Tuna (native name); Fig. 86.--An erect-stemmed, flat-jointed,
robust-growing species. Joints ovate, 4 in. to 9 in. long, with cushions
1 in. apart, composed of short, fulvous bristles, and several long,
needle-shaped, unequal, yellowish spines. Flowers borne on the upper
edges of the last-ripened joints, 3 in. across, reddish-orange, produced
in July. Fruit rich carmine, about 3 in. long, pear-shaped. The plant is
a native of the West Indies, &c., and was introduced in 1731. It has
already been stated, under O. spinosissima, that there is a close
similarity between that species and O. Tuna. We suspect, also, that O.
nigricans is another near relation of these two. They are much alike in
all characters, and they require the same treatment. O. Tuna has been
seen as much as 20 ft. in height.

[Illustration: FIG. 86. OPUNTIA TUNA.]

O. tunicata (coated-spined).--Stem sub-erect, cylindrical. Joints
club-shaped, variable in length, about 2 in. in diameter. When young the
surface is broken up into numerous oblong tubercles, each bearing a
small cushion of whitish, short hairs, and about half a dozen white
spines, unequal in length, the longest stout, and inclosed in a hard
sheath, which becomes broken and ragged when old. Flowers not known. A
native of Mexico, and introduced in 1840. It requires stove treatment.

O. vulgaris (common); Bot. Mag. 2393.--A low, prostrate, spreading
plant. Joints short, oval, flattened, thicker than in O. missouriensis,
3 in. long by about 2 in. broad. Spine-cushions 3/4 in. apart; tufts very
small, with, occasionally, a long spine. Leaves fleshy, very small.
Flowers 2 in. across, pale sulphur-yellow. Fruits nearly smooth, 11/2 in.
long, brown when ripe, with a strong disagreeable odour. The flowers are
produced freely in June. The plant grows wild in Mexico, and extends up
to New York, usually near the coast. It is now common in many parts of
Europe, where it has become naturalised. In Madeira it has taken
possession of all waste l