m PHVTOIiOGIST. 
Vol. VI., No. 2 . 
February 28 th, 1907 . 
LECTURES ON THE EVOLUTION OF THE 
FILICINEAN VASCULAR SYSTEM. 1 
By A. G. Tansley, M.A., 
Lecturer on Plant Anatomy at University College, London. 
Introductory. 
HE present course of lectures will be confined to the “ Ferns” 
proper and certain allied groups, i.e. to the Botryopterideae 
and related forms, the great Leptosporangiate series (including 
Osmundacese, which will however be treated separately), the 
Marattiales (including Psaronieae) and finally the Ophioglossales. 
The remaining groups of Pteridophytes and the Pteridospermje 
will only be alluded to at the beginning and at the close of the 
course, when a brief comparison between the course of evolution of 
the Filicinean vascular system and that of the other phyla of 
vascular plants will be attempted. 
The subject matter of the course will be mainly what has been 
called the “ gross anatomy ” of the vascular system, i.e., the forms 
and relationships of the vascular strands of the plant body. Histo¬ 
logical details will be dealt with only in so far as they appear to 
have a direct bearing on the general relations of the vascular 
strands. 
It will be well to state at the outset that I have been led to 
take a view of the morphology of the relationship between stem- 
stele and leaf-trace different from that suggested by Boodle, 2 and 
apparently to some extent assumed by professed anatomists who 
1 A Course of Advanced Lectures on Botany given for the 
University of London at University College during the second 
term of the Session, 1906-7. 
2 Boodle. Comparative Anatomy of the Hymenophyllaceje, 
Schizaeacea: and Gleicheniacea^ IV., p. 529. Ann. of Bot. 
18, 1903. 
