JUNIPKRUS 245 



SYNOPSIS OF SPECIES 



i . Ray cells (tangential) oval to round or transversely oval, 



resinous, conspicuously broad 

 Ray cells (radial) resinous throughout. 



4. * J. californica. 



Ray cells (radial) locally resinous. Rays usually higher (tangential) than 

 in No. 4 



5. J. utahensis. 



2. Rays (tangential) rather broad, the cells oval to round, chiefly 



round, sometimes in pairs, resinous 

 Bordered pits (radial) numerous, usually more or less distant. 



Rays (tangential) rather high, more or less 2-seriate or the cells in 

 pairs ; the cells chiefly very round, rarely transversely oval. 



9. J. pachyphlasa. 



Rays (tangential) low, the cells rarely in pairs, round to oval, not trans- 

 versely oval 



1. * J. virginiana. 



Bordered pits (radial) numerous, usually crowded into compact series. 

 Rays (tangential) with conspicuously and uniformly rounded cells. 



10. J. monosperma. 



3. Ray cells (tangential) chiefly oval, the rays low, barely resinous 

 Summer wood of 2-4, rarely of 10, tracheids. 



Pits on the lateral walls of the ray cells chiefly 2 per tracheid. 



1 1. J. occidentalis. 

 Summer wood conspicuously thicker. 



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



6. J. sabinoides. 



4. Rays (tangential) narrow, the cells oblong to oval, chiefly oblong 

 Pits on the lateral walls of the ray cells chiefly 2 per tracheid, Ray cells 

 resinous. 



Terminal walls of the ray cells strongly pitted. 

 Rays with narrow tracheids. 



7. J. communis. 

 Terminal walls of the ray cells thin and not pitted. 



Rays without tracheids. 



3. J. rigida. 



Pits on the lateral walls of the ray cells large, 2-4 per tracheid, obscurely 



and irregularly bordered. 



2. J. nana. 



Pits on the lateral walls of the ray cells not very large, chiefly 4 per 

 tracheid. Ray cells sparingly resinous. 



8. J. sabina. 



