A PLANT MORPHOLOGICALLY CONSIDERED. 
analogy between the skeleton of the leaf, and the skeleton of the branch, may be seen in a number of 
points as well as in the general resemblance between the ramification of the plant and the ramification 
of the venation of the leaf. (1.) Some trees, such as the Beech, the Elm, the Oak, the Holly, the 
Portugal and Bay Laurels, the Privet, the Box, will be found to send out side branches along the axis 
from the root, or near the very root, and the leaves of those trees have little or no petiole or leaf stalk, 
hut begin to expand from nearly the very place where the leaf springs from the stem. There are 
other trees, as the Common Sycamore (the Scotch Plane Tree), the Peach, the Chestnut, the Pear, the 
Cherry, the Apple, which have a considerably long unbranched trunk, and the leaves of these trees 
will be found to have a pretty long leaf stalk. (2.) Most of our low-branching herbaceous plants, such 
as the Mallows, Rhubarb, Tussilago, Marsh Marigold, Lady's M antic, Hollyhocks, send out a consider- 
able number of stems from near the root, and it will be found in exact accordance with this, that those 
set off from the base of the leaf, a considerable number of main veins or ribs, which, as they spread, 
cause the leaf to assume a rounded shape. In these plants, the morphological resemblance between 
tree and plant is seen horizontally and not vertically. In this respect these plants are different from 
our forest trees, which send up commonly one main axis with lateral branches, and have in their 
venation one leading vein with side veins, (3.) Some trees, such as the Beech, the Birch, the Elm, 
send up one large main stem, from which, throughout its length, there proceed comparatively small 
branches, pretty equal along the axis, and it will be found in such cases that the leaf has a central 
vein with pretty equally disposed veins on either side. Other trees again tend rather to send off at 
particular heights a number of comparatively thick branches at once. This is the case, for instance, 
with the common Sycamore, the Chestnut, and the Laburnum. The trunk of the Sycamore (Acer 
Pseudo platanus), about eight or ten feet above the surface of the ground, commonly divides itself into 
four or five large branches, and, in precise analogy, we find the leaf at the top of a pretty long leaf- 
stalk sending off four or five large veins. The Chestnut tends to send off at the top of the unbranched 
trunk a still greater number of branches ; and we find, in correspondence with this, that its leaf is 
commonly divided into seven leaflets. The Laburnum (and also the Broom and Clover) goes off in 
triplets in respect of leaflet and ramification. In such cases it will commonly be found that the leaf is 
compound ; and we are to regard all such compound leaves as one and representative of the whole tree. 
Generally, it is the whole leafage coming off at a given place which represents the whole tree, and the 
single leaf, when there is a number of leaves, represents merely the branch. (4.) Some plants, such as 
the Rhododendron, the Azalea, and the Lupine, send off leaves which have a tendency to become 
whorled, and then- branches have also a tendency to become verticillate. (5.) The stems of some trees, 
such as the Thorn and Laburnum, are not straight, and the branches have a twisted form ; and it will 
be found that the vein of the leaf of these trees is not straight, and that the leafage is not in one plane. 
This is also seen in the Elm. (6.) In some trees, such as the Beech, the stems go off in nearly straight 
lines, and the leaves are found to have a straight venation. In other trees again, such as the Chestnut, 
the branches have a graceful curve, and the veins of the leaves are curved in much the same way. 
(7.) In most plants the angle at which the side stems go off will be found to widen as we ascend to the 
middle, and thence to decrease as we ascend to the apex, and the venation of the leaves will be found 
to obey a similar law. This helps to give both to tree and leaf their beautiful oval outline. In some 
plants again, such as the Poplar and Birch, the angles are widest at the base, and tend to narrow as 
we ascend ; and both leaf and tree in such cases assume a kind of triangular form. (8.) Generally we 
shall find a correspondence between the angle of the ramification of the tree and the angle of venation 
of the leaf. We have made a sufficient number of measurements to be able to say that there is often such a 
correspondence. But it should be acknowledged, that while it is not difficult to determine the angle 
of the venation of the leaf, it is most difficult to determine what is the normal ramification of the tree, 
for the angle at which the branch goes off is liable to be modified by a great number of circumstances. 
All that we argue for is a general correspondence between the tendency of the direction of the branches 
and the tendenc}- of the direction of the veins of the leafage ; a tendency liable, however, to be affected 
by a great number of circumstances, natural and artificial. It is always to be remembered, that it is 
the whole leafage coming out at a givenplace, which represents the tree ; and the single leaf, where there 
are more leaves than one, represents the branch or the young tree. It is only thus that I can bring 
the Ash and Mountain Ash into accordance with these views. The whole leafage with its stalk 
represents the tree, and the leaf branch and leaflet the branches and branchlets, as also the young tree. 
Such facts as these strongly incline us to the belief, that in plants with leaves that strike the eye, 
/) the leaf and plant are typically analogous. The leaf is a typical plant or branch, and every tree or 
rv branch is a typical leaf. I am quite aware of the differences between these two distinct members of 
It 
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