SHOOTS 



71 



they do not need to be exposed to the light. Stems hearing 

 only scale leaves, tlierel'ore, hold no necessary liglit-rehitiori, 

 and may be subterranean as well as aerial. For the same 



i'lG. 6^. A group of weeping birches, showing tlie braiicliin;^ habit and llie pt-culiar 

 hanging branchiets. The trunlis also show the hubit of birch baric in peeling off 

 in bands around the stem. 



reason scale leaves do not need to be separated from one 

 anotlier, but may overlap, as in the buds referred to. 



Sometimes scale leaves occur so intermixed with foliage 

 6 



