CHAP. II. 
STEM. 
71 
between two nodes is called an intemode {merithallus, Du Petit 
Thouars). In internodes the arrangement of the vascular 
and woody tissue, of whatever nature it may be, of which they 
are composed, is nearly parallel, or, at least, experiences no 
horizontal interruption. At the nodes on the contrary, vessels 
are sent olf horizontally into the leaf ; the general develope- 
ment of the axis is momentarily arrested while this horizontal 
communication is effecting, and all the tissue is more or less 
contracted. In many plants this contraction, although it 
always exists, is scarcely appreciable ; but in others it takes 
place in so remarkable a degree as to give their stems a pecu- 
liar character ; as, for instance, in the Bamboo, in which it 
causes diaphragms that continue to grow and harden, notwith- 
standing the powerfully rapid horizontal distention to which 
the stems of that plant are subject. In all cases, without 
exception, a leaf-bud or buds is formed at a node immediately 
above the base of the leaf; generally such a bud is either 
sufficiently apparent to be readily recognised by the naked 
eye, or, at least, it becomes apparent at some time or other ; 
but in certain plants, as Heaths, the buds are often never 
discoverable ; nevertheless, they always exist, in however rudi- 
mentary a state, as is proved by their occasional developement 
under favourable or uncommon circumstances. By some 
writers nodes, upon which buds are obviously formed, are 
called compound^ or artiphyllous ; and those in which no appa- 
rent buds are discoverable, are named simple, or pleiophyllous; 
they are also said to be divided, when they do not surround 
the stem, as in the apple and other alternate-leaved genera; or 
entire, when they do surround it, as in grasses and umbelliferous 
plants : they are further said to be pervious, when the pith 
passes through them without interruption ; or closed, when the 
canal of the pith is interrupted, as if by a partition. Per- 
vious and divided, and closed and entire nodes usually accom- 
pany each other. For other remarks upon this subject, see 
Link’s Elemenfa, and the Appendix to this volume. 
All the divisions of a stem are in general terms called 
branches (rami) ; but it is occasionally found convenient to 
designate particular kinds of branches by special names. 
Thus, the twigs, or youngest shoots, are called ramuli, or 
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