THE BRUSH PILE 29 



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 cir- 

 cuits of the stem (passed twice around it) and had passed 

 over five spaces between buds. This is the leaf-arrange- 

 ment 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 ter- 

 minal 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 com- 

 pleted that early. This shoot bore leaves on the 2/5 ar- 

 rangement; 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). 



In 1921 these buds on No. 1, then, would have grown. 

 New leaves would have come from the bud itself; in fact, 



