Fig. 90. Twining or voluble stem of Morning-Glory.
91. Certain kinds of stems or branches, appropriated to special uses, have received distinct substantive names; such as the following:
[92.] A Culm, or straw-stem, such as that of Grasses and Sedges.
[93.] A Caudex is the old name for such a peculiar trunk as a Palm-stem; it is also used for an upright and thick rootstock.
[94.] A Sucker is a branch rising from stems under ground. Such are produced abundantly by the Rose, Raspberry, and other plants said to multiply "by the root." If we uncover them, we see at once the great difference between these subterranean branches and real roots. They are only creeping branches under ground. Remarking how the upright shoots from these branches become separate plants, simply by the dying off of the connecting under-ground stems, the gardener expedites the result by cutting them through with his spade. That is, he propagates the plant "by division."
[95.] A Stolon is a branch from above ground, which reclines or becomes prostrate and strikes root (usually from the nodes) wherever it rests on the soil. Thence it may send up a vigorous shoot, which has roots of its own, and becomes an independent plant when the connecting part dies, as it does after a while. The Currant and the Gooseberry naturally multiply in this way, as well as by suckers (which are the same thing, only the connecting part is concealed under ground). Stolons must have suggested the operation of layering by bending down and covering with soil branches which do not naturally make stolons; and after they have taken root, as they almost always will, the gardener cuts through the connecting stem, and so converts a rooting branch into a separate plant.
[96.] An Offset is a short stolon, or sucker, with a crown of leaves at the end, as in the Houseleek (Fig. [91]), which propagates abundantly in this way.
