Looking along the shoot, I find that every six buds stand in the same line: the sixth bud is over the first, seventh over the second, eighth over the third. If I were to fasten a string to bud No. 1 and wind it around the stem to my left, passing over every bud until I had reached the sixth, I should find that it had made two circuits of the stem (passed twice around it) and had passed over five spaces between buds. This is the leaf-arrangement or phyllotaxy of the apple-tree, expressed by the fraction 2/5. The space between two buds is two-fifths of a diameter, and two circuits (ten-fifths) must be passed before a bud comes over the one from which we started. The 2/5 leaf-arrangement obtains on cherry, peach, apricot, pear, raspberry and many others; but a very different order is that of the linden, grape, currant, lilies, elm, maple. We cannot understand this simple unbranched terminal twig (No. 1) until we know what took place last year. A year ago, in the spring of 1920, a terminal bud that had formed in 1919 expanded and gave rise to this rapidly growing shoot. By the end of May or early June this shoot had grown to twelve inches long, for the growth in length on the twigs of trees is usually completed that early. This shoot bore leaves on the 2/5 arrangement; in the axil of every leaf was a bud, the strongest buds being with the strongest leaves at the middle and top of the shoot; in the autumn of 1920 these leaves fell, but the buds remained, persisted the winter, and were ready to "grow" in the early spring of 1921. We see them on No. 1 (Fig. 14). [Illustration: 15. The growing shoot, with a bud in each axil, and a spur on last year's growth.] In 1921 these buds on No. 1, then, would have grown. New leaves would have come from the bud itself; in fact, the winter buds of the apple are packed with miniature leaves and sometimes with flowers as well. The shoot coming out of the bud may remain very short, constituting a "spur," or grow with long internodes, making a slender twig. Fig. 15 shows a branch with new elongated growth, _b_ to _a_, and a shoot or spur (_c_) arising from a bud of the previous year. Note the "ring," or division beyond _b_, marking the turn of the year. It will be noted in Fig. 14 that the buds are of two shapes and sizes, such as _a, a, a_, representing one kind and _b, b_, the other kind. The former, small and pointed, are leaf-buds; from them will arise a shoot bearing only leaves. The latter, _b_, large and rounded and usually more fuzzy, are flower-buds (fruit-buds): from them will arise a short shoot bearing leaves and a cluster of flowers; and we hope that at least one of the flowers will set fruit. We are now ready to resume our lesson with the branch before us. We have identified the slender terminal part, No. 1, as the growth of 1920. We are now to account for all the remaining buds and branchlets.