but the component leaflets of the one, are usually much larger than those of the other. The like contrasts are still more marked between triple leaves and simple leaves. This connection of decreasing size with decreasing composition, is conspicuous in the series of figures: the differences shown being not nearly so great as may be frequently observed. Confirmation may be drawn from the fact that when the leading shoot is broken or arrested in its growth, the shoots it gives off (provided they are given off after the injury), and into which its checked currents of sap are thrown, produce leaves of five leaflets where ordinarily leaves of three leaflets occur. Of course incidental circumstances, as variations in the amounts of sunshine, or of rain, or of matter supplied to the roots, are ever producing changes in the state of the plant as a whole; and by thus affecting the nutrition of its leaf-buds at the times of their formation, cause irregularities in the relations of size and composition above described. But taking these causes into account, it is abundantly manifest that a leaf-bud of the bramble will develop into a simple leaf or into a leaf compounded in different degrees, according to the quantity of assimilable matter brought to it at the time when the rudiments of its structure are being fixed. And on studying the habits of other plants--on observing how annuals that have compound leaves usually bear simple leaves at the outset, when the assimilating surface is but small; and how, when compound-leaved plants in full growth bear simple leaves in the midst of compound ones, the relative smallness of such simple leaves shows that the buds from which they arose were ill-supplied with sap; it will cease to be doubted that a foliar organ may be metamorphosed into a group of foliar organs, if furnished, at the right time, with a quantity of matter greater than can be readily organized round a single centre of growth. An examination of the transitions through which a compound leaf passes into a doubly-compound leaf, as seen in the various intermediate forms of leaflets in Fig. 65, will further enforce this conclusion. [Illustration: Figs. 50–64.] [Illustration: Fig. 65.]