TEANSACTIONS 



OF THE 



SCOTTISH AEBOETCULTUEAL SOCIETY, 



X. On the Anatomical Structure of the Leaf as a, means of determin- 

 ing the species of Abies. By W. R. M'Nab, M.D., Professor 

 of Botany, Royal College of Science, Dublin. (With Plate.) 



In 1874 Dr C E. Bertrancl of Paris published a work on the 

 comparative anatomy of the stems and leaves of the Gnetacese and 

 Coniferse.* In that work, after giving an historical sketch of the 

 literature of the subject, he describes the minute anatomy of the 

 leaves of most of the important genera, and in many cases gives 

 synoptic tables by which the species of certain of the genera may 

 be determined. In the present essay I propose to state very 

 briefly the results of an independent investigation, made during 

 the past eighteen months, on the anatomy of the leaves of the 

 various species of Abies of Link (Picea, Don) and Pseitdotsuga, 

 Carriere {Abies of authors). In so doing, I hope to be able to 

 correct many errors that Bertrancl seems to have committed, 

 owing probably to the imperfection of the materials at his com- 

 mand ; and, further, to throw some light on the obscure synonymy 

 of this extremely interesting group of plants. 



In examining the structure of the leaves of the species of Abies, 

 it is chiefly necessary to obtain good transverse sections from the 

 middle of the leaf. These must be thin and accurately cut, and 

 are best rendered suitable for careful examination by being placed 

 in a solution composed of equal parts of glycerine and water. 

 The slices require to be examined with a moderate magnifying 

 power, say of from 80 to 100 diameters. The chief points to notice in 



* ' ' Anatomie comparee des tiges et des feuilles chez les Gnetaceas et les 

 Coniferes, " par C. E. Bertrand. Paris: G. Masson, 1874. 



VOL. VIII., PART II. G 



