BUDS AND RAMIFICATION. 103 
same reason, also, they are rarely of great diameter. Some 
Ferns, however, become forked at their apex (jig. 204) ; which 
forking is produced by the division of the terminal bud into 
two (true dichotomy), from each of which a branch is formed (see 
page 109). But such branches are very different from those of 
dicotyledonous stems, which are produced from lateral buds, for, 
as they arise simply from the splitting of one bud into two, the 
diameter of the two branches combined is only equal to that of 
the trunk, and in all cases where acrogenous stems branch, the 
diameter of the branches combined is only equal to that of the 
axis from whence they are derived. As acrogenous stems only 
grow by the development of a terminal bud, the destruction of 
that bud necessarily leads to their death (page 106). There is 
nothing in the internal structure or external appearance of such 
stems by which we can ascertain their age. 
2. Bups anp Ramirication.—We have already stated (page 
14) that the presence of leaves and leaf-buds is the essential 
characteristic by which a stem may be distinguished from a 
root. The leaves will be treated of hereafter, but we have 
now to allude to the parts of the stem from whence they arise, 
and to describe the nature of leaf-buds, and the mode in which 
branches are formed. 
Leaves are always developed at regular points upon the 
surface of the stem, which are called nodes (fig. 208, c, c, c), and 
the intervals between them are termed internodes, d, d. Gene- 
rally the arrangement of the tissue of the stem at the nodes is 
somewhat different to that in the internodes; thus at a node it 
exhibits a more or less contracted or interrupted appearance, 
which arises from a portion of its fibro-vascular tissue being given 
off to enter into the structure of the leaf. This appearance 
is most evident in those cases where the internodes are clearly 
developed and especially if under such circumstances the leaf 
or leaves which arise encircle the stem, as in the Bamboo and 
other Grasses ; in such plants each leaf causes the formation of 
a hardened ring externally (fig. 201, b), and thus produces the 
appearance of a joint or articulation, and indeed, in some cases, 
the stem does readily separate into distinct portions at these 
joints, as in the common Pink, in which case it is said to be jointed 
or articulated. 
A. Lxrar-Bups or Bups.—Under ordinary circumstances we 
have developed in the axil of every leaf a little more or less 
conical body called a leaf-bud, or simply a bud (jig. 205, a, a). 
In like manner, the apex of a stem, as well as of all its main 
branches and twigs which are capable of further elongation, is 
also terminated bya similar bud (jig. 207). Ina Dicotyledonous 
plant each bud, whether lateral or terminal, is produced by an 
elongation of the parenchymatous system of the stem or one of 
its divisions, and consists at first of a minute conical central 
parenchymatous mass (jig. 206, i), which is connected with the 
