SEQUOIA 223 



pitted or locally thickened; the lateral walls with small, oval pits, 

 the orifice broadly lenticular, 1-2 or in the marginal cells and low 

 rays upwards of 8 per tracheid. Bordered pits elliptical in one row, 

 sometimes in pairs, numerous, about one half the diameter of the 

 tracheid. Pits on the tangential walls of the summer wood confined 

 to the outermost wall, not large, flat, rather numerous, often obscure. 

 Resin cells few, 12.5 p. wide, about 135 ^ long. 



Tangential. Rays low to medium, very narrow, strictly i -seriate ; the cells 

 uniform, thin-walled, oblong. 



9. * SEQUOIA, ENDL. PLATES 36 AND 37 



Trans-verse. Growth rings chiefly narrow, the usually thin summer wood 

 distinct. Resin cysts when present forming a continuous row on the 

 outer face of distant growth rings. Tracheids large, thin-walled, 

 square. Resin cells scattering, chiefly in the spring wood, or more 

 rarely wholly in the summer wood (S. Penhallowii). 



Radial. Rays without tracheids, but the marginal cells sometimes crystal- 

 logenous (S. Penhallowii). Pits of the ray cells with a narrow border, 

 the orifice commonly parallel with the cell axis. Pits often occur on 

 the tangential walls of both spring and summer tracheids. Terminal 

 walls of the ray cells rarely, if at all, pitted, except in S. Penhallowii. 

 Tracheids wholly without spirals. Radial resin passages wanting 

 except in S. Burgessii and S. Penhallowii, when they contain promi- 

 nent thyloses. 



Tangential. Fusiform rays usually wanting, or present in S. Burgessii and 

 S. Penhallowii. 



SYNOPSIS OF SPECIES 



Resin passages wholly wanting. 



Resin cells more or less numerous and scattering throughout the 

 growth ring. 



Bordered pits large, oval, conspicuously in 1-2 rows. 



Ray cells (tangential) of the spring wood very large and 

 broad, squarish. 



Pits on the lateral walls of the rays cells 2-6 per 

 tracheid. 



1. S. sempervirens. 

 Bordered pits in i or sometimes 2 rows. 



Ray cells (tangential) large, broad, squarish, or as often 

 transversely oblong. 



5. * * S. magnifica. 

 Ray cells (tangential) broadly oval or round. 



Pits on the lateral walls of the ray cells 1-2, or rarely 

 3-4, per tracheid. 



2. S. gigantea. 



