AS AIDS IN THE DETERMINATION OF SPECIES. 53 



(c) Wood-curve almost always entire, and ordi- 

 narily thick — 



11. E. globulus. 

 B. Vessels of Wood small — 



(1) Section large and epidermis of average thickness — 



12. E. alpina. 



(2) Section of average size and epidermis thin — 



13. E. viminalis. 

 /). Hard Bast poorly developed — 



A. Vessels of Wood relatively large — 



(1) Section large, twice as broad as thick — 



14. E. leucoxylon. 



(2) Section of average size — 



(a) Epidermis relatively thick — 



16. E. grossa. 



(b) Epidermis of average thickness — 



16. E. occidentalis. 



B. Vessels of wood small — 



(1) Section twice as broad as thick — ■ 



17. E. cornuta, var. lehmauni. 



(2) Section as broad as thick — 



18. E. obcordata. 

 2. Cortical Cavities small — 



a. Hard Bast well-developed — 



A. Epidermis relatively thin — 



19. E. stuartiana. 



B. Epidermis of average thickness — 



20. E. melhodora. 



b. Hard Bast feebly developed — 



A. Wood-curve excessively thick — 



21. E. amygdalina. 



B. Vessels medium-sized — 



22. E. rostrata. 

 c, Vessels comparatively small — 



(1) Epidermis thicker — 



23. E. rudis. 



(2) Epidermis thinner — 



24. E. tereticornis. 



Section II. B. may be further subdivided according to the size of the cortical 

 cavities and the development of the hard bast. 



