FOLIAGE LEAVES: THE LIGHT-RELATION 



27 



leaves (see i'igs. I'J, 2:'). In the ease of ordinary sluidc trees 

 every direction of branch may be found, and the resulting 

 adjustment of leaves noted (see Fig. 20). 



Looking up into a tree in full foliage, it will be noticed 

 that the horizontal branches are comparatively bare be- 



FiG. 22. A mosaic of fern {Adiantum) leaflets. 



neath, "while the leaf blades have been carried to the npper 

 side and have assumed a mosaic arrangement. 



Sprays of maidenhair fern (see Fig. 22) show a remark- 

 able amount of adjustment of the leaflets to the light side. 

 Another group of fern-plants, known as club-mosses, has 

 horizontal stems clothed witli numer(ms very small leaves. 

 Tliese leaves mav l)e seen taking advantage of all the space 

 on the lighted side (see Fig. 21), 



