CHAPTER III 
LIFE HISTORY OF A GYMNOSPERM (PINUS STROBUS) 
The White Pine frequently called the Weymouth Pine ( Pinus 
Strobus), one of the principal timber trees of the Northern States 
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. 
DESCRIPTION OF THE WHITE PINE TREE (MATURE 
SPOROPHYTE) 
From an underground spreading root system there arises an erect 
aerial trunk or stem that extends from the ground to the apex of the 
tree, ending in a terminal bud. The trunk rarely exceeds 3 feet in 
diameter and 125 feet in height and is averagely iK to 3 feet in 
diameter and 50 to 90 feet high. At a varying distance above the 
soil, depending upon environal conditions as well as the age of plant, 
whorls of lateral branches (three to seven in a whorl) are seen ema- 
nating from the trunk in horizontal fashion at various levels up to 
near the apex. These become, under conditions prevalent when the 
tree is grown in the open, gradually shorter until the summit is 
reached, giving to the crown or upper part of the tree the appearance 
of a pyramid. These branches give rise to other branches which 
agree with the lateral branches in bearing commonly only scale-like 
leaves as well as ending in terminal buds. Another kind of branch, 
however, is found which is always shorter than the scaly branches. 
This type of branch is called a “spur shoot ” and arises from the 
former branches. The spur shoots bear the needles or foliage leaves 
which are light green when young and bluish-green, soft, flexible, 
2 l 2 to 5 inches long when mature. The “needles” occur in tufts 
( fascicles ) of five, are triangular in cross-section, have finely serrate 
( saw-toothed ) edges and are surrounded at the base by a deciduous 
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