ABIES 253 



11. J. occidentalis, Hook. 



Juniper 



Trans-verse. Growth rings usually very narrow ; the dense summer wood of 

 2-4, rarely 10, tracheids, passing rather abruptly into the rather open 

 spring wood ; the tracheids small and thick-walled. Spring wood 

 rather open, but the tracheids rather small and usually much rounded. 

 Resin cells abundant and prominent, chiefly in the summer and outer 

 spring wood, in open or compact zones. Medullary rays numerous, 

 rather prominent, not very resinous, i cell wide, distant 2-8, rarely 

 13, rows of tracheids. 



Radial. Ray cells very sparingly resinous, usually straight or somewhat 

 contracted at the ends, equal to 4-6 spring tracheids ; the upper and 

 lower walls thickish, entire or distantly pitted ; the terminal walls 

 strongly pitted ; the lateral walls with small, oval, bordered pits, the 

 orifice oblong, 1-3, more rarely 4, per tracheid throughout. Bordered 

 pits round, numerous, in i row, becoming obscure or wanting in the 

 summer wood. Pits on the tangential walls of the summer tracheids 

 numerous, but usually small and often obscure. Resin cells numerous, 

 20 p. wide, 140-275 p. long. 



Tangential. Rays generally low, of a few cells only ; the cells round to 

 oblong, not very broad, chiefly oval. 



A tree 6-15 m. high, with a trunk 1.20-2.10 m. in diameter ; often becoming 



a low, much-branched shrub. 

 Wood light, soft, very close grained, compact, very durable in contact with 



the soil. 



Relative specific gravity 0.5765 



Percentage of ash residue 0.12 



(Sargent) 



Dry, rocky ridges and prairies of the Blue Mountains and high prairies of 

 eastern Washington and Oregon ; the Cascade Mountains of Oregon ; the 

 valley of the Klamath River, California, and south along the high ridges 

 of the Sierra Nevada Mountains at elevations of 7000-10,000 feet, to 

 the San Bernardino Mountains (Sargent). 



12. * ABIES, LINK. PLATES 42 AND 43 



Transverse. Growth rings usually broad with no very clear demarcation 

 between the spring and summer woods. Resin passages sometimes 

 present and then imperfectly organized, usually in somewhat distant 

 growth rings. Resin cells, when present, remote and inconspicuous 

 on the outer face of the summer wood. 



Radial. Ray tracheids not present (except A. balsamea). The terminal 

 walls of the ray cells usually strongly pitted, especially in the summer 

 wood. Tracheids wholly without spirals. 



Tangential. Fusiform rays wholly wanting. Rays narrow, strictly r-seriate. 



