ON TIM: PROTECTION OF BUDS 73 



stem. The second and third pairs of leaves on the 

 axillary shoot (when the latter develops) are reduced 

 to scales, which decussate with the spines. True leaves 

 follow the scales. 



Protection by the Leaf-base or the Leaf-stalk 



The axillary buds are thus protected in most 

 Composites, Umbellifers, in the whole family of the 

 Garyophyllaceon (Pink family), except Spergula and 

 Spergidaria, in the Gentians, 

 and many other families. 



In all these species the base 



of the petiole is more or less 



dilated, so as the more effec- C~ ~~\ 



tually to protect the bud. 



Fig. 110. Section across 

 Fig. 110 represents a sec- the Stem of a Walnut. 

 . , i o L, petiole : B, bud ; <S, shoot. 



tion across the stem of a ' ' 

 Walnut (Juglans nigra). It shows the bud, B, lying 

 between the stem, S, and the dilated base of the 

 leaf-stalk, L. The protection is more complete than 

 the figure indicates, because in nature the parts touch, 

 while for clearness a small space has been left between 

 them in the illustration. 



In the Box Elder (Negundo aceroides) (figs. 111,112), 

 a near ally of the Maples, the base of the petiole is 

 also widened, concave, almost covering the axillary bud, 

 and attached to the axis by a wide and deeply horse- 

 shoe-shaped base. The interior of the concavity is 



