PICEA 283 



Pits on the lateral walls of the ray cells with an oblong, 

 narrow orifice, 3-5 per tracheid, in the summer wood 

 reduced to 2, and finally to I. 



Spring tracheids large, squarish-hexagonal, very unequal 

 in regular rows, the walls thin. 



5. P. jesoensis. 



Pits on the lateral walls of the ray cells with a narrow, 

 oblong orifice, at first sometimes upwards of 7 per tra- 

 cheid, soon 2-4, and in the summer wood 1-2. 



Spring tracheids large, squarish, very uniform in regular 

 rows, the walls rather thin. 



2. P. rubra. 



Pits on the lateral walls of the ray cells with a narrow, 

 oblong orifice, becoming much extended in the summer 

 wood ; 2-3, more rarely 4, per tracheid, becoming i in the 

 summer wood. 



Spring tracheids distinctly hexagonal, conspicuously 

 unequal in regular rows, the walls not very thin. 

 i. P. Breweriana. 



1. P. Breweriana, Wats. 



Weeping Spruce 



Transverse. Growth rings rather thin and uniform. Summer wood rather 

 thin, of about 10-16 tracheids, prominent, not very dense, the tran- 

 sition from the spring wood gradual ; the tracheids unequal, in 

 rather regular rows, usually much compressed. Spring tracheids dis- 

 tinctly hexagonal, conspicuously unequal, in regular rows, the walls 

 not very thin. Resin passages rather numerous, scattering, often in 

 small groups, and more or less imperfectly formed ; the epithelium 

 in 1-2 rows of very variable but thick-walled, often resinous, cells. 

 Medullary rays prominent, resinous, distant 2-8, more rarely 12, rows 

 of tracheids. 



Radial. Rays sparingly resinous ; the ray tracheids marginal. Ray cells 

 straight or becoming fusiform in the summer wood, equal to 6-7 

 spring tracheids ; the terminal walls coarsely pitted ; the upper and 

 lower walls rather thick, unequal, more or less obscurely pitted except 

 in the summer wood ; the lateral walls with conspicuously bordered, 

 round, or oval pits, with an oblong orifice which becomes much ex- 

 tended in the summer wood, 2-3, more rarely 4, per tracheid, becoming 

 i in the summer wood. Bordered pits numerous, often much crowded, 

 in i row, elliptical. Pits on the tangential walls of the summer wood 

 rather numerous, not confined to the outermost tracheid wall. 



Tangential. Rays numerous, somewhat resinous, medium to high, not 

 very broad ; the cells chiefly equal and uniform, oblong, or more 

 rarely oval. Fusiform rays rather few, narrow ; the terminals often 

 much prolonged. 



