LAF 
was done by I’. Thomas in 1865. Further study was made upon the sub- 
ject by C. E. Bertrand in 1871-74 and W. B. McNab in 1875-77. However, 
the first man to study the subject closely was the late Dr. George Engel- 
mann, whose name is more intimately associated with the conifers than 
that of any other man. His first work along this line was his “Synopsis 
of American Firs,” which was published in 1878 in the Trans. St. Louis 
ABIES BALSAMEA. 
D Duets. M Mesophyll. 
B Bundle sheath. E Epidermis. 
F Fibro-vas. bundle. S Strength. cells. 
Acad. III, pp. 593-602. In 1880 there appeared in the same journal, IV, pp. 
161-189, his ““Revision of the Genus Pinus.’ However, in the second paper 
he merely used the internal structure to distinguish between the different 
subdivisions of the genus. 
It is at this point that J. M. Coulter and J. N. Rose took up the work. 
Their idea was to apply the characters obtained not only to the subdi- 
a 
