LARIX 279 



Radial. Rays somewhat resinous throughout ; the tracheids prominent, 

 numerous, and marginal. Parenchyma ray cells straight or barely 

 contracted in the summer wood ; the upper and lower walls thick, 

 unequal, and usually sparingly pitted ; the terminal walls coarsely 

 pitted throughout ; the lateral walls with distinctly bordered pits, the 

 narrow orifice chiefly oblong, 2-6 per tracheid, becoming distinctly 

 smaller toward the summer wood, where they are abruptly reduced to 

 2, and finally I, per tracheid. Bordered pits in I or 2 rows, large, 

 elliptical, becoming smaller and round toward the summer wood. 

 Pits often showing an equatorial band. Pits on the tangential walls 

 of the summer wood numerous, small, approximate, on the outer- 

 most tracheids only. The outer summer tracheids often show a 

 marked tendency to the formation of spirals. Resin cells 15 //.wide, 

 about 1 25 p. long. 



Tangential. Rays numerous, medium to high, sparingly resinous. The 

 fusiform rays with a broad central tract and a large resin canal 

 without thyloses. The ordinary rays rather broad, sometimes 2-seriate 

 in part ; the cells thick-walled, chiefly rather equal, uniform, oblong, 

 more rarely oval. Rays somewhat contracted at the position of the 

 narrow and interspersed tracheids. 



A tree 24-30 m. high, with a trunk upwards of .90 m. in diameter. Wood 

 heavy, hard, very strong, rather coarse grained, compact, durable in 

 contact with the soil. 



Relative specific gravity 0.6236 



Percentage of ash residue 0.33 



Approximate relative fuel value 62.16 



Coefficient of elasticity in kilograms on millimeters . . 1261. 



Ultimate transverse strength in kilograms 384. 



Ultimate resistance to longitudinal crushing in kilograms 8763. 



Resistance to indentation to 1.27 mm. in kilograms . . 1675. 

 (Sargent) 



Cold, wet swamps, often covering extensive areas, or northward on moist 

 uplands and intervale lands. This tree, together with the black spruce, 

 dominates nearly all the swampy land from Newfoundland, Labrador, and 

 the eastern provinces of Canada to the Rocky Mountains ; northward 

 to latitude 65, where it is reduced to a height of 6-8 feet (Macoun); 

 southward through the northern United States to northern Pennsylvania, 

 northern Indiana, Illinois, and central Minnesota (Sargent). 



A well-defined, widely distributed, and common tree in the Pleistocene 

 and more recent deposits, where the remains are preserved in a natural 

 state, and often most perfectly. 



Leda clays, Montreal; Scarborough Heights, Ontario; Moose River, 

 Ontario ; Lower Till of Fort Madison, Iowa ; Ithaca, New York ; Don 

 Valley, Toronto ; the black clays of the Columbian Formation (equiva- 

 lent to Pleistocene of northern localities) at Dahlonega, Georgia ; peat 

 bogs of New Brunswick. 



