212 ANATOMY OF THE GYMNOSPERMS 



Very durable in the soil. 



Relative specific gravity 0.4760 



Approximate fuel value 46.96 



Coefficient of elasticity in kilograms on millimeters . . 401. 



Ultimate transverse strength in kilograms 249. 



Ultimate resistance to longitudinal crushing in kilograms 5625. 



Resistance to indentation to 1.27 mm. in kilograms . . 1962. 

 (Sargent) 



Mendocino County, California, and along the western slope of the Sierra 

 Nevadas to Tulare County, at elevations of 3000-5000 feet (Sargent). 



3. T. nucifera, Sieb. et Zucc. 



Jap. Kaya 



Transverse. Growth rings rather narrow ; the tracheids of the spring wood 

 large, often distinctly squarish, passing gradually into the conspicuous 

 but narrow summer wood of about 10 tracheids, which again becomes 

 equal to the spring wood. Medullary rays prominent, i cell wide, dis- 

 tant 2-1 o rows of tracheids. 



Radial. Cells of the medullary rays not contracted at the ends, equal to 

 about 6 tracheids ; the upper and lower walls medium, remotely and 

 obscurely pitted; the terminal walls thin, not pitted or locally thick- 

 ened, diagonal or straight, rarely curved ; the lateral walls with small, 

 conspicuously bordered, oval pits with a diagonal, linear-oblong ori- 

 fice, about 2-6, or, in the summer wood, i per tracheid. Bordered 

 pits in i series, or in pairs, forming 2 imperfect series, distant, 

 the outer margin rather obscure, the orifice lenticular and diagonal 

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

 wanting. Spirals of the tracheids prominent, distant 5-25 yu., in double, 

 triple, or quadruple series, the angle 70.5, in the summer wood 

 becoming vestigial in the outer tracheids. 



Tangential. Rays numerous, low to medium, the walls of the cells rather 

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



Japan. 



2. * TAXUS, TOURN. PLATES 22 AND 23 



Transverse. Growth rings variable, often unconformable. The summer 

 wood dense and conspicuous, though often very thin ; the tracheids 

 small throughout and more or less rounded, the structure somewhat 

 dense or more rarely open (T. floridana), with large and squarish 

 tracheids. Resin passages and resin cells wholly wanting. 



Radial. Spirals of the tracheids rather close, 2-, rarely 3-seriate. 



Tangential. Ray cells narrowly oblong. Fusiform rays wholly wanting. 



SYNOPSIS OF SPECIES 



A. Tracheids small, rounded, thick-walled 

 Rays low, i -seriate. 



Growth rings variable, sometimes double. 



2. * T. canadensis, Willd. 



