342 ANATOMY OF THE GYMNOSPERMS 



38. P. Sabiniana, Douglas 



Digger Pine. Bull Pine 



Transverse. Growth rings thick, variable, often double. Summer wood 

 variable, upwards of one fourth to one half the spring wood, from which 

 the transition is somewhat abrupt, dense, or again rather open ; the 

 tracheids very unequal, chiefly in irregular rows, the larger ones often 

 much compressed. Spring tracheids rather large, squarish-hexagonal, 

 uniform in regular rows, the walls thickish. Resin passages medium, 

 not very numerous, chiefly in the summer wood : the epithelium of 2 or 

 more rows of large, irregularly flattened and very thin-walled, somewhat 

 resinous cells, often forming an irregular and somewhat extended tract. 

 Medullary rays prominent, somewhat resinous, broad, i cell wide, dis- 

 tant 2-10 rows of tracheids. 



Radial. Rays sparingly resinous ; the tracheids low but very variable, mar- 

 ginal, predominant and sparingly interspersed, often composing the 

 entire structure of low rays, strongly dentate and somewhat reticulate 

 in the summer wood. Ray cells of two kinds : (i) cells rather numerous, 

 chiefly in low rays ; the upper and lower walls thick, strongly but irreg- 

 ularly pitted ; the lateral walls with prominent, round and bordered, or 

 simple and lenticular pits, 2-5, chiefly 4, per tracheid ; (2) cells rather 

 low and variable, not conspicuously fusiform ; the terminal, upper, and 

 lower walls very thin and entire ; the lateral walls with variously lentic- 

 ular pits without an obvious border, 2-4, chiefly 2, per tracheid, becoming 

 reduced to i in the summer wood. Bordered pits conspicuously in 1-2 

 rows, numerous, elliptical, becoming smaller and round toward the summer 

 wood. Pits on the tangential walls of the summer wood wholly wanting. 



Tangential. Fusiform rays rather numerous, narrow ; the terminals acute 

 or prolonged linear, chiefly composed of tracheids ; the cells of the 

 inflated portion large and very thin-walled, often much broken out. 

 Ordinary rays chiefly low, not very numerous, nonresinous, broad, the 

 tracheids chiefly terminal and much narrower, rarely interspersed, pre- 

 senting four principal aspects: (i) thin-walled parenchyma with termi- 

 nal and interspersed tracheids; (2) i-seriate rays with a few terminal, 

 thick-walled tracheids, but chiefly composed of large and very thin-walled 

 parenchyma cells ; (3) thin-walled parenchyma with terminal tracheids 

 and interspersed, thick-walled parenchyma ; and (4) i-seriate rays com- 

 posed of tracheids and thick-walled parenchyma. 



A large tree 24-30 m. high, with a trunk upwards of 1.20 m. in diameter. 

 Wood light,soft,notstrong,brittle and very coarse grained, compact,not durable. 



Specific gravity 0.4840 



Percentage of ash residue 0.40 



Approximate relative fuel value 48.18 



Coefficient of elasticity in kilograms on millimeters .... 585. 



Ultimate transverse strength in kilograms 333. 



Ultimate resistance to longitudinal crushing in kilograms 5387. 

 Resistance to indentation to 1.27 mm. in kilograms . . 2202. 

 (Sargent) 



Very common in the foothills region : Coast Range and western slope of 

 the Sierra Nevadas below 4000 feet elevation, California (Sargent). 



