330 ANATOMY OF THE GYMNOSPERMS 



Tangential. Fusiform rays rather numerous and narrow, the terminals 

 somewhat prolonged but rather broad, the cells of the inflated portion 

 rather thick-walled, those of the terminals large and thin-walled. 

 Ordinary rays rather numerous, low to medium, much narrowed by 

 the numerous and very variable, interspersed, and predominant tra- 

 cheids ; the relatively few parenchyma cells often resinous, very 

 unequal and variable, oval, both thick- and thin-walled, the latter 

 often much broken out. 



A large tree 61-91 m. high, with a trunk 3.60-4.57 m. in diameter. 

 Wood variable in quality and value, hard, heavy, strong, brittle, not coarse 

 grained nor durable, compact. 



Specific gravity 0.4715 



Percentage of ash residue 0.35 



Approximate relative fuel value 50.28 



Coefficient of elasticity in kilograms on millimeters . . 824. 



Ultimate transverse strength in kilograms 279. 



Ultimate resistance to longitudinal crushing in kilograms 6292. 



Resistance to indentation to 1.27 mm. in kilograms . . 1740. 

 (Sargent) 



Interior of British Columbia south of latitude 51, thence southward along 

 the mountain ranges of the Pacific region to Mexico ; eastward to the 

 Black Hills of Dakota, Colorado, and western Texas. Dry, rocky ridges 

 and prairies, or in the northern portion of California, rarely in cold, wet 

 swamps, reaching its greatest development on the western slopes of the 

 California Sierras (Sargent). 



27. P. Coulteri, D. Don 



Pitch Pine 



Transverse. Growth rings thick, variable. Summer wood thin, upwards of 

 10 tracheids and open, the transition gradual ; the tracheids very vari- 

 able, rounded, and often much compressed, in conspicuously irregular 

 rows. Spring tracheids large, squarish-hexagonal, the walls rather 

 thin. Resin passages rather abundant, medium ; the epithelium in 

 i -several rows of large, rather thick-walled, and chiefly rounded cells, 

 nonresinous, often forming extensive and irregular tracts about the 

 canal. Medullary rays broad, i cell wide, rather prominent, distant 

 2-20 rows of tracheids. 



ial. Rays sparingly resinous throughout ; the tracheids low, often pre- 

 dominant, more or less reticulated throughout, and often composing 

 the entire structure in low rays. Parenchyma cells fusiform, of two 

 kinds: (i) high and prominent, especially in the low rays; the ter- 

 minal walls thin and not pitted ; the upper and lower walls thick and 

 coarsely pitted ; the lateral walls with round or oval and prominent pits, 

 1-4, more rarely 6, per tracheid, becoming 1-2 in the summer wood; 

 and (2) the cells fusiform, the terminal walls thin and not pitted ; the 

 upper and lower walls very thin, often much broken out, or again 



