284 ANATOMY OF THE GYMNOSPERMS 



A tree upwards of 30 m., or more rarely 36 m. in height, with a trunk 



.6o-.9o m. in diameter. 

 Wood soft, close grained, compact, with a satiny surface. 



Relative specific gravity 0.5141 



(Sargent) 



This tree occurs in small, scattered groves in the elevated mountain 

 regions of California and Oregon, between 4000 and 7500 feet altitude 

 (Sargent). 



2, P. rubra, Dietr. 

 Red Spruce 



Transverse. Growth rings narrow, rather variable. Summer wood narrow, 

 not very prominent, upwards of 10 tracheids, rather open; the tran- 

 sition from the spring wood gradual. Spring tracheids rather large, 

 not very thin-walled, in very regular rows and very uniform, squarish. 

 Resin passages widely scattering, not numerous, medium and equal 

 to about 2 tracheids ; the epithelium composed of rather small, thick- 

 walled cells ; wholly devoid of thyloses. Resin cells wholly wanting. 

 Medullary rays I cell wide, not numerous or prominent, distant 3-14 

 rows of tracheids. 



Radial. Rays sparingly resinous, the resin usually localized and more or 

 less confined to the thicker-walled and more strongly pitted cells ; the 

 ray tracheids prominent, marginal, rarely interspersed. Ray cells 

 straight throughout, or barely fusiform in the summer wood, equal to 

 about 5-7 spring tracheids; the terminal walls strongly pitted; the 

 upper and lower walls rather thin, distantly and obscurely pitted, 

 or in the summer wood more or less strongly pitted ; the lateral walls 

 with small, elliptical, bordered pits with an oblong orifice, at first 

 sometimes upwards of 7 per tracheid, soon 2-4, and in the summer 

 wood 1-2. Bordered pits broadly elliptical or round, in i row, not 

 crowded, but variable in size. Pits on the tangential walls of the 

 summer wood very small and much compressed. 



Tangential. Rays somewhat numerous, medium, sparingly resinous. Fusi- 

 form rays narrow, the resin canal small with thick-walled epithelium. 

 Ordinary rays not broad, medium, the cells very equal and uniform, 

 oblong, or sometimes oval throughout. 



A tree usually 21-24 ni., and occasionally 30-33 m. in height, with a 

 trunk .6o-.9o m. in diameter. 



Valley of the St. Lawrence and the northern shores of Prince Edward 

 Island, southward through Quebec, the Maritime Provinces, and along 

 the Atlantic coast to southern Maine and Cape Cod ; through the hilly 

 interior and the mountainous parts of New England and New York, 

 thence along the Allegheny Mountains to the high peaks of western 

 North Carolina (Sargent). 



