[Illustration: FIG. 14.--Lilac. I. Branch in winter state: _a_, leaf-scar; _b_, bud-scar (reduced). 2. Same, less reduced. 3. Branch, with leaf-buds expanded. 4. Series in a single bud, showing the gradual transition from scales to leaves.] That the scales are modified leaves is plainly shown by the gradual transition they undergo, and also by the fact that buds are developed in their axils. If any of these can be shown to the pupils, remind them of the experiment where the top of a seedling Pea was cut off and buds forced to develop in the axils of the lower scales.[1] The transition from scales to leaves can be well studied by bringing branches into the house, where they will develop in water, and towards spring may even be made to blossom. Cherry, Apple, Forsythia, and other blossoming trees and shrubs can be thus forced to bloom. Place the branches in hot water, and cut off a little of their ends under water. If the water is changed every day, and the glass kept near the register or stove, they will blossom out very quickly. These expanded shoots may be compared with the buds. The number of leaves in the bud varies. [Footnote 1: See p. 31.] The leaf-scars of Lilac are horseshoe-shaped and somewhat swollen. It can often be plainly seen that the outer tissue of the stem runs up into the scar. It looks as if there were a layer of bark, ending with the scar, fastened over each side of the stem. These apparent layers alternate as well as the scars. The epidermis, or skin of the leaves, is in fact always continuous with that of the stem. There are no dots on the leaf-scars. The rings are not nearly so noticeable as in Horsechestnut, but they can be counted for some years back. The flower-cluster can often be traced by a dried bit of stem remaining on the branch. The terminal bud in the Lilac does not usually develop, and the two uppermost axillary buds take its place, giving to the shrub the forked character of its branching. In all these bud studies, the pupil should finish by showing how the arrangement of the buds determines the growth of the branches. QUESTIONS ON THE LILAC. How do the scales differ from those of Horsechestnut? How many scales and leaves are there? How are they arranged? Where does the flower-cluster come in the bud? Do all the buds contain flower-clusters? How does the arrangement of leaves and flower-clusters differ from that of Horsechestnut? How old is your branch? Which buds develop most frequently? How does this affect the appearance of the shrub? COPPER BEECH (_Fagus sylvatica, var. purpurea_).