CHAPTER III 
LIFE HISTORY OF A GYMNOSPERM (PINUS STROBUS) 
The White Pine frequently called the Weymouth Pine [Finns 
Strobus), one of the principal timber trees of the Northern States 
Pig. 19.—Transverse section of white pine stem ol four years’ growth, showing 
cork (a), cortex (6), phloem (c), cambium (d), xylem ( e ), secretion reservoir (/), 
pith (g) and medullary ray (h). (Photomicrograph.) X 340 - 
and Canada, is also of value in pharmacy and medicine. The inner 
bark of its trunk and branches is used because of its valuable ex¬ 
pectorant properties and is official in the N. F. IV. 
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