234 



ANATOMY OF THE GYMNOSPERMS 



Radial '. Ray tracheids chiefly short and broad ; chiefly or wholly confined 

 to rays i or 2 cells high, then constituting the entire ray, not very 

 numerous. Kay cells somewhat resinous, more or less conspicuously 

 contracted at the ends, equal to 4-9 spring tracheids ; the upper and 

 lower walls thick and entire or distantly pitted ; the terminal walls 

 thin and locally thickened; the lateral walls with rather small pits 

 with a lenticular orifice often parallel with the cell axis, 1-4 per 

 tracheid. Bordered pits round or elliptical in i row, somewhat distant ; 

 the round orifice often very variable, much enlarged, eccentric, 

 irregular in outline or even wanting, the pits then presenting a vari- 

 able aspect which at once serves to define the species. Pits on the tan- 

 gential walls of the summer tracheids few, often obscure. Resin cells 

 few, about 20 p. wide and 100-175 /u, long, rarely upwards of 270 /t. 



Tangential. Rays low, narrow, and i-seriate, sometimes 2-seriate in part ; 

 'the cells narrowly elliptical or broadly oval, sometimes transversely 

 oval or oblong, much enlarged. 



This is the most variable species of Cupressus, and it is chiefly remarkable 

 for the variable character of the summer wood, the irregular disposition 

 of the tracheids (transverse), the often very numerous resin cells, and 

 the peculiarly imperfect bordered pits which at once separate it from 

 all other species. It may show deviation from the normal in (i) the 

 absence of resin cells ; (2) the form of the tracheids, which are some- 

 times round with thick walls, even in the same section, thus giving rise 

 to (3) a variable structure of the wood which is in some rings rather 

 dense throughout. 



A large tree of great economic importance with a height of 30-38 m. and 

 a diameter of 1.20-1.80 m. Wood light, hard, and very durable. 



Relative specific gravity 0.4782 



Approximate relative fuel value 47.66 



Coefficient of elasticity in kilograms on millimeters . . 1029. 



Ultimate transverse strength in kilograms 342. 



Ultimate resistance to longitudinal crushing in kilograms 7281. 



Resistance to indentation to 1.27 mm. in kilograms . . 1618. 

 (Sargent) 



Interior of Vancouver Island ; British Columbia, near the coast, where 

 it reaches sea level in the northern portions, and thence to Alaska 

 (Macoun) ; southward through the Cascade Mountains of Washington 

 and Oregon, where it is seldom found below an elevation of 5000 feet 

 (Sargent). 



5. C. obtusa, Sieb. et Zucc. 



Jap. II i n ok i 



Transverse. Growth rings broad. Summer wood chiefly rather thin, some- 

 times double, rather open but passing very gradually into the broad 

 spring wood from which it is not clearly separable. Tracheids of the 

 spring wood round-hexagonal, thickish-walled, not very large, the 



