WINTER CONDITION OF SHOOTS AND BUDS 65 



107. Shoots of the lilac. The shoots of the lilac have the 

 same arrangement of the lateral buds and leaf scars as those of 

 the horse chestnut. They are opposite and in pairs, and each 

 pair alternates in position with the pair above and 



below. The leaf scar is much smaller and semi-lunar 

 in shape. The outer bud scales are brown, while the 

 inner ones are green, and some of the intermediate 

 ones have brown tips and green bases. There is one 

 interesting point of difference, however, between the 

 shoots of the lilac and those of the horse chestnut. 

 The shoot appears to have a pair of terminal buds 

 which stand slightly divergent. There is a leaf scar 

 at the base of each one which shows that these buds 

 are axillary; i.e., they arise in the axils of the leaves. 

 They are, therefore, axillary terminal buds. This 

 would indicate that the true terminal bud was sub- 

 ordinate. This is true. If we search carefully between 

 the pair of axillary terminal buds there is found a 

 minute dead terminal bud on the scar, left where it 

 has fallen away. This indicates that the shoots of 

 the lilac have indefinite or indeterminate growth. 

 Those of the horse chestnut have determinate growth. 

 The pair of axillary terminal buds of the lilac form, 

 the following year, a pair of shoots which diverge, or 

 fork. Some of these buds, however, are flower buds, 

 as can be determined by dissecting them. 



108. Shoots of the elm. The elm represents still 

 another type of shoot, as shown by the position of 

 the buds. The buds are alternate, and are situated 

 in two rows on opposite sides of the shoot. The 



shoots are more or less zigzag in outline, the buds situated 

 at the angles thus formed. On the ascending or horizontal 

 shoots the rows of buds are lateral, so that as they develop 

 into shoots the branching system cf a limb presents a flattened 

 outline, which is more marked when the leaves are present, since 

 shoots and leaves lie in nearly the same plane. On either side of 



Fig. 60. 

 Shoot of lilac. 



