142 



FOUNDATIONS OF BOTANY 



like those of the horse-chestnut, but they are found to be 

 arranged more nearly flatwise along the inner portions 

 of the branches, that is, the portions nearer the tree. 

 Figs. 109 and 110 show the remarkable difference in 

 arrangement in different branches of the Deutzia, and 

 equally interesting modifications may be found in 

 alternate-leaved trees, such as the elm and the cherry. 



Fig. 109. — Opposite Leaves of Deutzia* (from tlie same shrub as Fig. 110), as 

 arraQged on a Horizontal Brancli. 



150. Leaf -Mosaics. — In very many cases the leaves at 

 the end of a shoot are so arranged as to form a pretty 

 symmetrical pattern, as in the horse-chestnut (Fig. 107). 

 When this is sufficiently regular, usually with the space 

 between the leaves a good deal smaller than the areas of 

 the leaves themselves, it is called a leaf-mosaic (Fig. 111). 

 Many of the most interesting leaf-groups of this sort (as 



1 Deutzia crenata. 



