312 ANATOMY OF THE GYMNOSPERMS 



the position of the very narrow and small, interspersed tracheids ; the 

 parenchyma cells rather equal but variable from broadly to nar- 

 rowly oval, the thin side walls sometimes strongly inflated, rarely 

 incurved. 



A large tree 46-92 m. high, with a trunk upwards of 7 m. in diameter. 

 Wood very light, soft, coarse, but straight grained, compact, satiny, and 

 easily worked. 



Specific gravity 0.3684 



Percentage of ash residue 0.22 



Approximate relative fuel value 36.76 



Coefficient of elasticity in kilograms on millimeters . . . 794. 



Ultimate transverse strength in kilograms .... . 255. 



Ultimate resistance to longitudinal crushing in kilograms 5382. 



Resistance to indentation to 1.27 mm. in kilograms . . 1244. 

 (Sargent) 



Cascade and Coast Ranges of Oregon, where it descends to 1000 feet above 

 sea level, from the head of the Mackenzie River and the valley of the 

 Rogue, southward along the western flanks of the California Sierras, 

 where it reaches an elevation of 4000-8000 feet ; through the coast 

 ranges to the Santa Lucia Mountains, and in the San Bernardino and 

 Cuyamaca mountains (Sargent). 



8. P. monticola, D. Don 

 White Pine 



Transverse. Growth rings variable. Summer wood open and very thin and 

 imperceptibly passing into the spring wood, the tracheids in regular 

 rows, variable, squarish. Spring wood very open, the tracheids large 

 and squarish, rather thin-walled. Medullary rays prominent and resin- 

 ous, not numerous, rather broad, i cell wide, distant 2-17 rows of tra- 

 cheids. Resin passages very large, rather numerous, the epithelium 

 rather extensive and resinous. 



Radial. Rays conspicuously resinous throughout, the ray tracheids narrow, 

 marginal, often interspersed. Parenchyma ray cells straight ; the upper 

 and lower walls thin and entire or again with locally numerous, broad 

 pits, unequal ; the terminal walls thin and entire or again locally thick- 

 ened ; the lateral walls with very large, oval or oblong or lenticular 

 pits, chiefly 1-2 per tracheid throughout, in the summer wood reduced 

 to i with a lenticular orifice. Bordered pits round or elliptical, in i row 

 or sometimes in pairs. Pits on the tangential walls of the summer 

 wood small and narrowly lenticular, chiefly on the outermost wall. 

 Resinous tracheids wanting. 



Tangential. Fusiform rays not numerous, broad and high, the cells of the 

 inflated portion large and thin-walled, often much broken down. Ordi- 

 nary rays low to medium, strongly resinous, when of a few elements 



