58 
M. G. Sykes. 
V. From anatomical, developmental, and comparative 
evidence, it is concluded that the genus Lycopodium is to be regarded 
as reduced from some of the larger strobiloid Pteridophytes, and that 
the genus itself is also composed of forms which can be arranged 
in a reduction series and the evolution of which is still traceable among 
the species alive to-day. 
VI. If it be granted that the “sporophyll” of L. cernuum 
shows the more primitive arrangement, it would seem to me to be 
natural to regard it as an axial structure, morphologically 
equivalent to a reduced branch, which is terminated by a single 
sporangium, and bears also a single leaf, with which, however, its 
association need not necessarily be primitive. A similar interpre¬ 
tation has before been given to the sporophylls of some of the 
allied fossil and recent Pteridophytes. 
The work for this paper was begun at the Botany School, 
Cambridge, while holding a Bathurst Studentship at Girton College, 
and was continued in the Botanical Laboratory of the Royal 
Holloway College. 
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