11. Other buds.—Examine the buds of the beech, lilac, violet, dock, fern, etc., and make drawings showing (1) how the leaves are arranged with regard to each other, and (2) how each leaf is folded or rolled. As a rule these points can be easily made out by examining with a lens the cut surface of a bud which has been cut across with a sharp [Pg 58] knife; but the buds should also be examined at frequent intervals when they are unfolding. A typical bud.—An excellent idea of the structure of a typical bud can be obtained by splitting down the middle an ordinary cabbage, or a lettuce “heart,” and examining the manner in which the leaves crowd round and cover the conical end of the stalk. Around the tip or “growing point” the leaves are extremely small and tender. They are overlapped by slightly larger leaves, which spring from the stalk a little lower down. These in their turn are covered by still larger leaves, inserted at a yet lower level, and so on—the largest and oldest leaves folding over the smaller and more recently formed. The growing point of a stem, or of a branch of a stem, surrounded by a cluster of immature leaves, is called a bud. The history of a sycamore twig.—The student who would know the meaning of the various marks and scars on the surface of a twig, should select one and follow carefully for a year the fate of the buds which it bears. It is convenient to begin by studying a twig on a sycamore tree. It may be marked for ease of recognition by tying a piece of tape on it. If several students are working, each should write his name or number on a luggage-label and fix this to his twig. Fig. 33.—Sycamore leaves and fruits. (From a photograph by Mr. A. Flatters.) (× ¹ ₁₂.) [Pg 59] The positions of the buds.—In summer the younger twigs of the sycamore tree are covered with large five-pointed leaves (Fig. 33). The leaves come off in pairs, each pair being at right angles to the pair next above or below. Every leaf is engaged throughout the day in building up—by means of the green stuff in its interior—starch and other foods (p. 50), and in giving off excess water, in the form of invisible vapour, through its stomata (p. 53). In the axil (p. 47) of each leaf is a little bud, called from its position an axillary bud (Fig. 41, B), and at the very tip of the twig is a larger terminal bud.