[Illustration:  FIG. 18.—­Branch of Cherry in winter state:  a, leaf-scar; b, bud-scar; c, flower-scar.]

[Illustration:  FIG. 19.—­Branch of Red Maple in winter state (reduced). 2.  Flower-buds]

The leaves are needle-shaped and short.[1] They are arranged densely on the branches, alternately on the 8/21 plan (see section on phyllotaxy).  When they drop off they leave a hard, blunt projection which makes the stem very rough.  As the terminal bud always develops unless injured, the tree is excurrent, forming a straight trunk, throwing out branches on every side.  The axillary buds develop near the ends of the branchlets, forming apparent whorls of branches around the trunk.  In the smaller branches, as the tree grows older, the tendency is for only two buds to develop nearly opposite each other, forming a symmetrical branch.

[Footnote 1:  The pupils should observe how much more crowded the leaves are than in the other trees they have studied.  The leaves being smaller, it is necessary to have more of them.  Large-leaved trees have longer internodes than those with small leaves.]

The bud-scales are persistent on the branches and the growth from year to year can be traced a long way back.

The cones hang on the ends of the upper branches.  They are much larger than in our native species of Black and White Spruce.

The Evergreens are a very interesting study and an excellent exercise in morphology for the older scholars.

2. Vernation.  This term signifies the disposition of leaves in the bud, either in respect to the way in which each leaf is folded, or to the manner in which the leaves are arranged with reference to each other.  The pupils have described the folding of the leaves in some of their specimens.

In the Beech, the leaf is plicate, or plaited on the veins.  In the Elm, Magnolia, and Tulip-tree, it is conduplicate, that is, folded on the midrib with the inner face within.  In the Tulip-tree, it is also inflexed, the blade bent forwards on the petiole.  In the Balm of Gilead, the leaf is involute, rolled towards the midrib on the upper face.

Other kinds of vernation are revolute, the opposite of involute, where the leaf is rolled backwards towards the midrib; circinate, rolled from the apex downwards, as we see in ferns; and corrugate, when the leaf is crumpled in the bud.

[Illustration:  FIG. 20.—­Branch of Norway Spruce.]

In all the trees we have studied, the leaves simply succeed each other, each leaf, or pair of leaves, overlapping the next in order.  The names of the overlapping of the leaves among themselves, imbricated, convolute, etc., will not be treated here, as they are not needed.  They will come under aestivation, the term used to describe the overlapping of the modified leaves, which make up the flower.[1]