uring summer. It
may be watered regularly whilst growing--that is, from April to
September--and kept quite dry all winter. The soil should be
well-drained loam, and the roots should have plenty of room. A specimen
may be seen in the Kew collection.

Propagation.--This may be effected from seeds, or by removing the head
from an old plant, putting the former in sand, and placing it under a
bell-glass to root, watering it only about once a week till roots are
formed. The old stem should be kept dry for about two months, and then
watered and placed in a sunny, moist position, where it can be syringed
once a day. A shelf in a stove is the best position for it. Here it will
form young buds in the axils of the withered tubercles, and on the edges
of the persistent parts of the tubercles themselves. They first appear
in the form of tiny tufts of yellowish down, and gradually develop till
the first leaf-like tubercle appears. When large enough, the buds may be
removed and planted in small pots to root. If an old plant is dealt with
in this way in April, a batch of young ones should be developed and
rooted by October. Grafting does not appear to have ever been tried for
this plant. When sick, the plant should be carefully washed, and all
decayed parts cut away; it may then be planted in very sandy loam, and
kept under a bell-glass till rooted.

[Illustration: FIG. 74. LEUCHTENBERGIA PRINCIPIS.]

SPECIES.

L. principis (noble); Fig. 74.--This, the only species known, was
introduced from Mexico to Kew in 1847, and flowered the following year.
The plant attains a height of 1 ft. or more, the stem being erect, stout,
clothed with the persistent, scale-like bases of the old, fallen-away
tubercles, the bases having dried up and tightened round the stem. The
upper part is clothed with the curved, leaf-like tubercles, from 3 in. to
6 in. long, grey-green in colour, succulent, with a tough skin,
triangular, and gradually narrowed to a blunt point, upon which are half
a dozen or more thin, flexuous, horny filaments, neither spines nor
hairs in appearance, but almost hay-like; the central one is about 5 in.
long, and the others about half that length. The flowers are borne on
the ends of the young, partly-developed tubercles, near the centre of
the head; they are erect, tubular, 3 in. to 4 in. long, scaly, gradually
widening upwards; the sepals and petals are numerous, and form a
beautiful flower of the ordinary Cactus type, quite 4 in.