CUPRESSUS 229 



Radial. Rays chiefly without trachcids. Terminal walls of the ray cells thin 

 and entire, very commonly curved, often locally thickened. Tracheids 

 wholly without spirals. 



Tangential. Fusiform rays wholly wanting. Ray cells chiefly broad, oval, or 

 even transversely oval ; the rays sometimes 2-seriate in part. 



SYNOPSIS OF SPECIES 



A. * CHAM/ECYPARIS 



Existing Species 



1. Pits on the tangential walls of the summer tracheids flat, 



small, obscure, or at least not prominent 

 Ray cells (tangential) round or oval. 

 Ray tracheids absent. 



Tracheids more or less conspicuously rounded throughout. 

 Ray cells (radial) straight, sparingly resinous. 



Pits on the lateral walls of the ray cells 2, in radial 

 series, or in the marginal cells 6, per tracheid. 



5. C. obtusa. 

 Tracheids distinctly squarish, large, the structure open. 



Pits on the lateral walls of the ray cells 2-4, rarely 8, per 



tracheid. 



2. C. Lawsoniana. 



Pits on the lateral walls of the ray cells 2, in radial series, 



or 6, per tracheid. 



3. C. pisifera. 



Ray tracheids present in the low rays. 



Tracheids distinctly squarish, or again rounded and thick-walled, 

 the structure variable, either open or somewhat dense. 



Pits on the lateral walls of the ray cells 1-4 per tracheid. 

 Tracheids (transverse) commonly in very irregular rows. 



4. C. nootkatensis. 

 Ray cells (tangential) narrow, oblong, more rarely oval. 



Tracheids distinctly squarish, in regular rows, the structure open. 



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

 cells and low rays upwards of 6, per tracheid. 



i. C. thyoides. 



B. CUPRESSUS 



Existing Species 



2. Pits on the tangential walls of the summer tracheids chiefly 



large and open 

 Ray cells (tangential) round or oval, more rarely transversely oval. 



