264 ANATOMY OF THE GYMNOSPERMS 



6-11 spring tracheids, becoming shorter in the summer wood: the 

 upper and lower walls rather thick, unequal, and conspicuously pitted 

 throughout ; the terminal walls rather sparingly pitted, especially in 

 the spring wood ; the lateral walls with round or elliptical, small, 

 obscurely bordered pits, which become distinctly bordered toward the 

 summer wood, where the broadly lenticular orifice becomes oblong 

 or finally slitlike, 1-3 per tracheid throughout the spring wood, becom- 

 ing i in the summer wood. Bordered pits rather numerous in i row, 

 elliptical or round. Pits on the tangential walls of the summer tra- 

 cheids rather numerous but not very large, flat. Pits rarely on the 

 tangential walls of the earlier spring tracheids. Resin cells rarely to 

 be seen. Resin passages imperfectly formed of short, cylindrical resin 

 cells, in interrupted series. 



Tangential. Rays numerous, medium to high, not very broad ; the cells 

 chiefly uniform, oval, sometimes round or oblong, rarely large. 



A tree 30-40 m. in height, with a trunk 1.20-1.50 m. in diameter. 

 Wood very light, soft, not strong, coarse grained, compact. 



Relative specific gravity ........... 0.3638 



Percentage of ash residue ........... 0.85 



Approximate relative fuel value ......... 36.07 



Coefficient of elasticity in kilograms on millimeters . . 909. 

 Ultimate transverse strength in kilograms ..... 300. 



Ultimate resistance to longitudinal crushing in kilograms 6237. 



Resistance to indentation to 1.27 mm. in kilograms . . 1248. 

 (Sargent) 



Moist slopes and canons between 3000 and 9000 feet elevation, reach- 

 ing its greatest development in the California Sierras ; northern slopes 

 of the Siskiyou Mountains of Oregon ; south along the western slope of 

 the Sierra Nevadas to San Bernardino and San Jacinto Mountains of 

 California ; the high mountains of Arizona to the Mogollon Mountains 

 of New Mexico ; northward to Pikes Peak and the Wasatch Moun- 

 tains of Utah (Sargent). 



11. A. firma, Sieb. et Zucc. 



Jap. j 



Transverse. Growth rings broad, the dense summer wood about one 

 fourth the spring wood, into which it passes gradually. Spring wood 

 open, the tracheids thin-walled, in very regular rows, uniform, large. 

 Resin cells and resinous tracheids wanting. Medullary rays rather 

 prominent and sparingly resinous, I cell wide, distant 2-10 rows of 

 tracheids. Resin canals present but imperfectly organized, forming 

 local or sometimes extensive tangential rows on the outer face of the 

 summer wood of distant growth rings. 



Radial. Medullary rays sparingly resinous, devoid of tracheids. Ray 

 cells straight, equal to 5-10 spring tracheids, in the summer wood 

 becoming much shorter and distinctly fusiform ; the upper and lower 



