144 



THE VEGETATIVE FUNCTIONS OE PLANTS 



oropposite leaves often do not appear to be opposite each 

 other, and are often of very unhke size. Such an arrange- 

 ment of the blades forms a leaf-mosaic (Figs. 102 and 103). 

 If a leaf is removed from a group, or even if a leaflet is 



Fig. 103. — Leaf-mosaic in the Boston ivy {Psedera tricuspidaia). 

 (Photo by the author.) 



removed from the blade of a compound leaf, the remaining 

 leaves or leaflets will alter their positions with reference 

 to each other so as to occupy the space most advan- 

 tageously and economically (Fig. 104). 



137. Advantages of Power of Adjustment.— Very little 

 thought will enable one to understand at once the pro- 



