=Arrangement of Buds.=--We have found that leaves are usually arranged in a definite order; buds are borne in the axils of leaves: therefore _buds must exhibit phyllotaxy_. Moreover, branches grow from buds: branches, therefore, should show a definite arrangement; usually, however, they do not show this arrangement because _not all the buds grow and not all the branches live_. (See Chaps. II and III.) It is apparent, however, that the mode of arrangement of buds determines to some extent the form of the tree: compare bud arrangement in pine or fir with that in maple or apple. [Illustration: FIG. 154.--OAK SPRAY. How are the leaves borne with reference to the annual growths?] The uppermost buds on any twig, if they are well matured, are usually the larger and stronger and they are the most likely to grow the next spring; therefore, branches tend to be arranged in tiers (particularly well marked in spruces and firs). See Fig. 154 and explain it. =Winter Buds show what has been the Effect of Sunlight.=--Buds are borne in the axils of the leaves, and the size or vigor of the leaf determines to a large extent _the size of the bud._ Notice that, in most instances, _the largest buds are nearest the tip_ (Fig. 157). If the largest ones are not near the tip, there is some special reason for it. Can you state it? Examine the shoots on trees and bushes. [Illustration: FIG. 155.--AN APPLE TWIG.] [Illustration: FIG. 156.--Same twig before leaves fell.] SUGGESTIONS.--Some of the best of all observation lessons are those made on dormant twigs. There are many things to be learned, the eyes are trained, and the specimens are everywhere accessible. =123.= At whatever time of year the pupil takes up the study of branches, he should look for three things: the ages of the various parts, the relative positions of the buds and leaves, the different sizes of similar or comparable buds. If it is late in spring or early in summer, he should watch the development of the buds in the axils, and he should determine whether the strength or size of the bud is in any way related to the size and vigor of the subtending (or supporting) leaf. The sizes of buds should also be noted on leafless twigs, and the sizes of the former leaves may be inferred from the size of the leaf-scar below the bud. The pupil should keep in mind the fact of the struggle for food and light, and its effects on the developing buds. =124.= _The bud and the branch._ A twig cut from an apple tree in early spring is shown in Fig. 155. The most hasty observation shows that it has various parts, or members. It seems to be divided at the point _f_ into two parts. It is evident that the part from _f_ to _h_ grew last year, and that the part below _f_ grew two years ago. The buds on the two parts are very unlike, and these differences challenge investigation.--In order to understand this seemingly lifeless twig, it will be necessary to see it as it looked