220 ANATOMY OF THE GYMNOSPERMS 



A lar^e tree 30-40 m. in height, with a trunk 1.20-2.10 m. in diameter. 

 The light, soft wood is very durable in contact with the soil. 



Relative specific gravity 0.4017 



Approximate relative fuel value ... 40.14 



Coefficient of elasticity, in kilograms on millimeters . . 847. 

 Ultimate transverse strength in kilograms 291. 



Ultimate resistance to longitudinal crushing in kilograms 7446. 



Resistance to indentation to 1.27 mm. in kilograms . . 1561. 

 (Sargent) 



Santian river, Oregon ; southward along the western slopes of the Cas- 

 cade and Sierra Nevada mountains at elevations of 3000-8500 feet, 

 thence through California Coast Range to the San Bernardino and Cayu- 

 maca mountains (Sargent). 



8. * THUYA, TOURN. PLATES 34 AND 35 



Transverse. Summer wood thin and dense. Resin passages wholly want- 

 ing. Resin cells more or less prominent, but often widely scattering. 

 Tracheids chiefly large and thin-walled, squarish. 



Radial. Ray tracheids wholly wanting except in T. japonica. Ray cells 

 usually conspicuously contracted at the ends ; the terminal walls thin 

 and not pitted or locally thickened, usually much curved. Tracheids 

 wholly without spirals. 



Tangential. Fusiform rays wholly wanting. Ordinary rays narrow, medium 

 'to low, strictly i-seriate, the cells chiefly narrowly oval to oblong. 



SYNOPSIS OF SPECIES 



Pits on the lateral walls of the ray cells 1-2, or in the marginal cells and 

 low rays upwards of 8 per tracheid. 



Pits on the tangential walls of the summer wood confined to the 

 outermost wall. 



3. T. japonica, Max. 



Pits on the lateral walls of the ray cells 1-4, or in the marginal cells and 

 low rays 6 per tracheid. 



Pits on the tangential walls of the summer wood not confined to the 

 outermost tracheid wall. 



1. T. gigantea, Nutt. 



Pits on the lateral walls of the ray cells 1-4, or in the marginal cells and 

 low rays 7 per tracheid. 



Pits on the tangential walls of the summer wood confined to the 

 outermost tracheid wall. 



2. * T. occidentalis, Linn. 



