A GREEN LEAF 



67 



one half of the leaf-tissue as a single layer of 

 large cells instead of several layers, as in the case 



tig. 45, The rieshy leaf of a stonecrop 



of the laurel and sunflower leaves. A difference 

 of this kind is but a minor matter. Some plants, 

 however, have to modify their leaf-structures 

 very much to adapt themselves to their particular 



