le (x1/2).]

CHAPTER XVII

GRAPE BOTANY

The grape-grower must know the gross structure and the habits of
growth of the plants properly to propagate, transplant, prune and
otherwise care for the grape. Certainly he must have knowledge of the
several species from which varieties come if he is to know the kinds
of grapes, understand their adaptations to soils and climates, their
relation to insects and fungi, and their value for table, wine,
grape-juice and other purposes. Fortunately, the botany of the grape
is comparatively simple. The organs of vine and fruit are distinctive
and easily discerned and there are no nearly related plants cultivated
for fruit with which the grape can possibly be confused. Botanists, it
is true, have dug pitfalls for those who seek exact knowledge as to
the names and characters of the many species, but, fortunately, each
of the cultivated species constitutes a natural group so distinct that
the grape-grower can hardly mistake one for another in either fruit or
vine.

PLANT CHARACTERS AND GROWTH HABITS OF THE GRAPE

A grape plant is a complex organism with its many separate parts
especially developed to do one or a few kinds of work. The part of a
plant devoted to one or a group of functions is called an organ. The
chief organs of the plant are the root, stem, bud, flower, leaf, fruit
and seed. Flowers and leaves, it is true, develop from buds and the
seeds are parts of the fruits, but for descriptive purposes the vine
may well be divided into the parts named. These chief organs are
further divided as follows:

_The root._

_Root-crown_: The region of the plant in which root and stem
unite.
_Tap-root_: The prolongation of the stem plunging vertically
downward.
_Rootlets_: The ultimate divisions of the root; usually of one
season's growth.
_Root-tips_: The extreme ends of the rootlets.

The roots of some species of the grape are soft and succulent as those
of _V. vinifera_, while the same organs in other species, as in most
American grapes, are hard and fibrous. They may also be few or
numerous, deep or shallow, spreading or restricted, fibrous or
non-fibrous. The structure of the root thus becomes important in
distinguishing species.

_The stem._

_Stem or trunk_: The unbranched main axis of the plant above
ground.
_Branches or arms_: Main divisions of the trunk.
_Hea