ON THE 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-EASE OR THE LEAF-STALK 



The axillary buds are thus protected in most 

 Composites, Umbellifers, in the whole family of the 

 Caryophyllacece (Pink family), except Spergula and 

 Spergularia, 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- 



tually to protect the bud. 



* FIG. 110. SECTION ACROSS 



Fig. 110 represents a sec- THE STEM OF A WALNUT. 



, , I f L, petiole : 11. bud ; 8, shoot. 



tion across the stem of a 



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

 between the stem, 8, 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 acerddes) (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 



