r
small cases in windows, these little Thimble Cactuses are amongst the
most suitable. They are natives of high mountains in Mexico, and have
been cultivated in Europe over forty years.

M. fissurata (fissured); Fig. 61.--In appearance, this rare species
mimics some of the Gasterias, and is so different from all the kinds
hitherto described, that very few people unacquainted with it would
suspect that it belonged to the same genus as M. elongata or M.
dolichocentra. Indeed, some botanists have made a separate genus of this
and several other plants of the same peculiar appearance, calling them
Anhalonium. M. fissurata is like a whip-top in shape, the root being
thick and woody, and the tubercles arranged in a thick layer, spreading
from the centre, rosette-like. A living plant in the Kew collection is
2 in. high by 4 in. wide, the tubercles being triangular in shape, 1/2 in.
thick, wrinkled, with an irregular furrow on the upper surface. The
flowers grow from the middle of the stem, and are 11/2 in. wide, and
rose-coloured. Native of Mexico, on hard gravel or limestone soils. We
know of no plant in English collections, except that at Kew, which was
introduced from Mexico in 1886. It flowers in September and October.

[Illustration: FIG. 61. MAMILLARIA FISSURATA.]

M. floribunda (free-flowering).--A French writer on Cactuses, M.
Labouret, calls this a species of Echinocactus, but it resembles so
closely another species included by him in Mamillaria, viz., M. atrata,
that we see no good reason for separating the two into different genera.
M. floribunda has an irregular conical stem, about 5 in. high by 4 in.
wide at the base, round nut-like tubercles the size of filberts, crowned
with star-tufts of spines 3/4 in. long, stiff, and brown, about ten spines
being set with their bases in a small disc-like pad of dirty-white wool.
The flowers are very numerous, covering the whole of the stem-top, from
which they stand erect, so as to form a dense bouquet of rose-coloured
petals. Each flower is 2 in. long. Native of Chili; introduced about
1835. Flowers in summer. This handsome kind will thrive in a window,
and, if well supplied with fresh air, sunshine, and sufficient water to
keep the soil moist, it will flower almost every year. It must have no
water in winter.

M. gracilis (slender).--A small Thimble Cactus, remarkable for its
proliferous stems, a single stem 2 in. high producing all round its upper
half numerous, offshoo