Page:An introduction to physiological and systematical botany (1st edition).djvu/166

 136 ''Fl. Austr. append. t.'' 17 they grow one under another for three successive seasons. The buds of the Plane-tree, ''Platanus, Du Hamel Arb. v.'' 2. 171, are concealed in the footstalk, which must be removed before they can be seen, and which they force off by their increase; so that no plant can have more truly and necessarily deciduous leaves than the Plane. Shrubs in general have no buds, neither have the trees of hot climates. Linnæus once thought the presence of buds might distinguish a tree from a shrub, but he was soon convinced of there being no real limits between them.

The situation of buds is necessarily like that of the leaves, alternate, opposite, &c. Trees with opposite leaves have three buds, those with alternate ones a solitary bud, at the top of each branch. Du Hamel.

Buds are various in their forms, but very uniform in the same species or even genus. They consist of scales closely enveloping each other, and enfolding the embryo plant or branch. Externally they have often an additional guard, of gum, resin or woolliness, against wet and cold. The Horse Chesnut,