252 ANATOMY OF THE GYMNOSPERMS 



round, numerous, becoming very small and obscure in the summer 

 wood, the round orifice becoming lenticular towards the summer wood. 

 Tits on the tangential walls of the summer tracheids numerous, medium, 

 flat. Resin cells about 20 p. wide, 165-400 /x long. 



Tangential. Rays medium, often 2-seriate in part, the cells broadly oval or 

 round, rather thick-walled. 



A tree 6-15 m. high and .60 m. in diameter. 



Wood light, soft, not strong, brittle, very close grained, compact, suscep- 

 tible of a fine polish. 



Relative specific gravity 0.5829 



Percentage of ash residue o. 1 1 



(Sargent) 



Mountains of western Texas, southern New Mexico, and Arizona south of 

 latitude 34; southward into Mexico (Sargent). 



10. J. monosperma, Sarg. 



Juniper 



Transverse. Growth rings chiefly broad, very variable. The prominent 

 but usually very thin summer wood dense, of 3-7 tracheids, often 

 double ; the transition from the spring wood somewhat gradual. Spring 

 wood somewhat dense, the tracheids variable. Resin cells very prom- 

 inent and resinous, numerous, in compact zones chiefly in the spring 

 wood. Medullary rays very numerous and prominent, broad, i cell 

 wide, distant i-io rows of tracheids. 



Radial. Ray cells resinous throughout, more or less conspicuously con- 

 tracted at the ends, equal to 6-8 spring tracheids ; the upper and lower 

 walls thick, rather uniform, frequently pitted ; the terminal walls 

 coarsely pitted; the lateral walls with small, round, bordered pits with 

 a lenticular-oblong but small orifice, chiefly 2, but in low rays and 

 marginal cells often upwards of 6, per tracheid. Bordered pits numer- 

 ous and in I compact row, round or vertically compressed, nearly 

 as broad as the tracheid. Pits on the tangential walls of the summer 

 tracheids very numerous but small. Resin cells about 15 p. wide, 200 p. 

 and upwards long. 



Tangential. Rays numerous, resinous, low ; the broad cells oval or round, 

 somewhat uniform. 



A stunted tree 6-9 m. high, and a trunk upwards of .60 m. in diameter. 



Relative specific gravity 0.7119 



Percentage of ash residue 0.78 



(Sargent) 



Gravelly slopes between 3500 and 7000 feet elevation, eastern base of 

 Pikes Peak, to the mountains of western Texas ; through New Mexico 

 and southern Arizona to southern California (Sargent). 



