70 
ORGANOGRAPHY. 
BOOK I. 
the cotyledons belongs to the stem, and it is only after the 
first joint of the stem, however minute and short it may be, 
is completed, that a root is formed. This will be more par- 
ticularly explained hereafter ; see Section XIV. of this chapter. 
As the double elongation just mentioned exists in all plants, 
it follows that all plants must necessarily have, at an early 
period of their existence at least, both stem and root ; and 
that, consequently, when plants are said to be rootless, or 
stemless, such expressions are not to be considered physio- 
logically correct. 
The Stem has received many names ; such as caudex 
ascendens, caudex intermedins^ culmus, stipes^ truncus^ and truncus 
ascendens. It consists of bundles of vascular and woody tissue, 
embedded in cellular substance in various ways, and the whole 
enclosed within an epidermis. The manner in which these 
parts are arranged with respect to each other will be explained 
hereafter. The more immediate subject of consideration 
must be those organs which are common to all stems. 
I. Of its Parts. 
Where the stem and root, or the ascending and descending 
axis diverge, there commences in many plants a difference 
of anatomical structure, and in all a very essential physiolo- 
gical dissimilarity; as will be hereafter seen. This portion of 
the axis is called the neck or collum, [coarcture of Grew, ncmid 
vital of Lamarck, limes communis, or fundus plantce, of Jungius,) 
and has been thought by some to be the seat of vegetable 
vitality ; an erroneous idea, of which more will be said in the 
next book. At first it is a space that we have no difficulty in 
distinguishing, so long as the embryo, or young plant, has 
not undergone any considerable change; but in process of 
time it is externally obliterated ; so that in trees of a few years’ 
growth its existence becomes a matter of theory, instead of 
being actually evident to our senses. 
Immediately consequent upon the growth of a plant is the 
formation of leaves. The point of the stem from whence these 
arise is called the node (genicidum, Jungius), and the space 
