CHAPTER V. 
BUDS AND LEAF ARRANGEMENT. 
It has already been pointed out that the two parts of the 
shoot, z.e., stem and leaf, are very closely connected, so that one 
cannot be defined without reference to the other. Leaves are, in 
fact, outgrowths from the side of the stem, which generally differ 
from it in shape, and are developed acropetally (figs. 2, 4, and 
5 A). Most leaves are flat, and, in a general sort of way, they 
may be looked upon as modified pieces of stem. Not uncom- 
monly the sides of a stem are produced into green wing-like 
expansions. If these, instead of being continuous, were very 
much developed at some points and reduced at others, something 
very like leaves would result. Curiously enough, some leaves 
actually do become continuous at their insertions, with wings on 
the stem, as in the thistle. 
There is much more to be said about the leaf than was the ° 
case either with the root or stem. Their arrangement will first 
be considered, and then the various kinds of leaf will be dealt 
with consecutively. 
Leaving the flower out of consideration for the present, imma- 
ture leaves have a certain arrangement in the bud, which leads 
up to the arrangement of the mature leaves on the fully-developed 
stem. 
Buds, as previously mentioned, are young shoots, in which all 
the parts are very small, and the internodes non-elongated. The 
best examples are to be found in trees, which may be instructively 
studied in early spring. Every branch typically ends in an apical 
or terminal bud, within which the year’s growth is, so to speak, 
mapped out, nothing but increase in size being needed to produce 
a leafy shoot (figs. 2, 4, and 5 A). In racemose branching (p. 24) 
a branch or twig may grow indefinitely in this way, an apical 
bud being formed every year ready for the next year’s growth. 
A very good instance is the horse-chestnut. An examination of 
an apical bud of this tree in spring will show a number of firm 
over-lapping scales on the outside, which are extremely sticky 
owing to the secretion of a resinous substance. <A longitudinal ~ 
