698 THE AMERICAN NATURALIST. [Vol. XXXV 1 11. 



Pinus, in which the most complete development is attained, and 

 it therefore terminates the series upwardly. 



Having special reference to the particular forms of the secre- 

 tory reservoirs, and leaving out of account all other considera- 

 tions than their particular evolution, it is possible to indicate the 

 general sequence of the genera and, to a more limited extent, of 

 their species, as follows : — 



1 . Tsuga caroliniana. 



2. Abies bracteata. 



" firma. 

 " nobilis. 

 " concolor. 



3. Sequoia. 



4. Pseudotsuga and Larix. 



5. Picea. 



6. Pinus. 



From this it is manifest that Sequoia is superior to Tsuga and 

 Abies but inferior to Pseudotsuga, Larix, etc. But if we now 

 view the general phylogeny with reference to the entire course 

 of development of the resm cells and the resin passages, the 

 relations just explained must be modified with reference to the 

 particular position of Sequoia, and the sequence would then 

 become : — 



1. Thuyopsis and Cryptomeria. 



2. Podocarpus. 



3. Cupressus. 



5. Libocedrus. 



6. Taxodium. 

 7- Juniperus. 

 8. Sequoia. 

 9- Tsuga. 



10. Abies. 



11. Pseudotsuga and Larix. 



12. Picea. 



13. .Pinus. 



