316 ANATOMY OF THE GYMNOSPERMS 



The following determinations are after Bovey : 

 Coefficient of strength in pounds for : 



Bending 4,800 



Torsion 1 0,000 



Compression 3>5 



Shear 34 



Weight per cubic foot 26 



One of the most valuable and widely spread trees of Canada, extending from 

 Newfoundland, Anticosti, Nova Scotia, and New Brunswick throughout 

 Quebec and Ontario, and westward nearly to Lake Winnipeg (Macoun) ; 

 southward through the northern United States to Pennsylvania, the south- 

 ern shores of Lake Michigan ; La Salle, Illinois ; Davenport, Iowa ; along 

 the Allegheny Mountains to northern Georgia (Sargent). 



Pleistocene deposits of the Don Period, Toronto. 



Material preserved in natural state, but showing the effects of extended decay. 



12. P. parviflora, Sieb. et Zucc. 



Jap. = Himekomatsu 



Transverse. Growth rings rather broad, the usually thin summer wood up- 

 wards of one half the spring wood, from which the transition is gradual. 

 Summer wood rather open, often double, the tracheids conspicuously 

 unequal, rounded-hexagonal. Spring tracheids rather large, squarish, 

 uniform, in regular rows, rather thin-walled, radially elongated. Med- 

 ullary rays not prominent or numerous, very narrow, i cell wide, distant 

 2-10 rows of tracheids. Resin passages large, rather numerous, the 

 epithelium composed of large and thin-walled cells. 



Radial. Rays nonresinous ; the tracheids low, marginal, rarely interspersed. 

 Parenchyma ray cells straight, equal to about 5-7 spring tracheids ; the 

 upper and lower walls very variable, chiefly rather thin, often distantly 

 and obscurely pitted ; the terminal walls thin and not pitted ; the lateral 

 walls with large, oval, or radially elongated simple pits, i, or in the 

 early spring wood 2, per tracheid, in the summer wood becoming verti- 

 cally lenticular. Bordered pits very large and narrowly elliptical, rather 

 numerous, in i row. Pits on the tangential walls of the summer wood 

 small, rather few and widely scattering, except on the outermost wall. 

 Resinous tracheids apparently wanting. 



Tangential. Fusiform rays broad, the large resin canal with prominent 

 thyloses and thin epithelium cells, the cells of the inflated portion all 

 thin-walled. Ordinary rays narrow, conspicuously contracted at the posi- 

 tion of the much narrower, occasionally interspersed tracheids ; the 

 parenchyma cells chiefly equal, rather thin-walled, somewhat variable, 

 chiefly oblong and narrow or sometimes oval and much broader, but 

 uniform in the same ray, the lateral walls concave, more rarely convex. 

 Resinous tracheids sparingly present, the resin in plates simulating 

 Sanio's bands. 



