with deeply channelled stems and the appearance of immense candelabra.
Totally devoid of leaves, and often skeleton-like in appearance, these
plants have a strange look about them, which is suggestive of some
fossilised forms of vegetation belonging to the past ages of the
mastodon, the elk, and the dodo, rather than to the living things of
to-day.

By far the greater part of the species of Cactuses belong to the group
with tall or elongated stems. "It is worthy of remark that as the stems
advance in age the angles fill up, or the articulations disappear, in
consequence of the slow growth of the woody axis and the gradual
development of the cellular substance; so that, at the end of a number
of years, all the branches of Cactuses, however angular or compressed
they originally may have been, become trunks that are either perfectly
cylindrical, or which have scarcely any visible angles."

A second large group is that of which the Melon and Hedgehog Cactuses
are good representatives, which have sphere-shaped stems, covered with
stout spines. We have hitherto spoken of the Cactuses as being without
leaves, but this is only true of them when in an old or fully-developed
state. On many of the stems we find upon their surface, or angles, small
tubercles, which, when young, bear tiny scale-like leaves. These,
however, soon wither and fall off, so that, to all appearance, leaves
are never present on these plants. There is one exception, however, in
the Barbadoes Gooseberry (Pereskia), which bears true and persistent
leaves; but these may be considered anomalous in the order.

The term "succulent" is applied to Cactuses because of the large
proportion of cellular tissue, i.e., flesh, of their stems, as compared
with the woody portion. In some of them, when young, the woody system