known as _layering_. It is
a simple process. Just bend the tip of a bough down and bury it in the
earth (see Fig. 47). The black raspberry forms layers naturally, but
gardeners often aid it by burying the over-hanging tips in the earth, so
that more tips may easily take root. Strawberries develop runners that
root themselves in a similar fashion.

Grafts and buds are really cuttings which, instead of being buried in
sand to produce roots of their own, are set on the roots of other
plants.

[Illustration: FIG. 45. ROSE CUTTING]

Grafting and budding are practiced when these methods are more
convenient than cuttings or when the gardener thinks there is danger of
failure to get plants to take root as cuttings. Neither grafting nor
budding is, however, necessary for the raspberry or the grape, for these
propagate most readily from cuttings.

It is often the case that a budded or grafted plant is more fruitful
than a plant on its own roots. In cases of this kind, of course, grafts
or buds are used.

The white, or Irish, potato is usually propagated from pieces of the
potato itself. Each piece used for planting bears one eye or more. The
potato itself is really an underground stem and the eyes are buds. This
method of propagation is therefore really a peculiar kind of cutting.

Since the eye is a bud and our potato plant for next year is to develop
from this bud, it is of much importance, as we have seen, to know
exactly what _kind_ of plant our potato comes from. If the potato is
taken from a small plant that had but a few poor potatoes in the hill,
we may expect the bud to produce a similar plant and a correspondingly
poor crop. We must see to it, then, that our seed potatoes are drawn
from vines that were good producers, because new potato plants are like
the plants from which they were grown. Of course when our potatoes are
in the bin we cannot tell from what kind of plants they came. We must
therefore _select our seed potatoes in the field_. Seed potatoes should
always be selected from those hills that produce most bountifully. Be
assured that the increased yield will richly repay this care in
selecting. It matters not so much whether the seed potato be large or
small; it must, however, come from a hill bearing a large yield of fine
potatoes.

[Illustration: FIG. 46. BEGONIA-LEAF CUTTING]

Sweet-potato plants are produced from shoots, or growing buds, taken
from the potato itself, so that in their case too the