229 
Pteridophytes . Are they vestigial? 
phylls and the sporophylls. But abortion, partial or complete, 
does take place at the apex. It will be a matter for sub- 
sequent discussion what is the comparative bearing of these 
facts. 
Lycopodium. 
This genus was divided by Spring 1 according to the 
distribution of the sporangia, an arrangement which is main- 
tained, with amendments, by Baker in his Fern- Allies 2 . 
In dealing with the abortion of sporangia, and their distribu- 
tion upon the plant, I shall follow Baker’s arrangement, giving, 
in the order of the species in his work, the details which 
I have thought worthy of note for the present purpose, after 
looking through the herbaria of Kew, and of Glasgow 
University. 
By adopting for the present purpose Baker’s arrangement, 
I do not deny that it is open to such amendments as have 
been proposed elsewhere 3 . 
Sub-genus. Selago. 
Group of L . Selago. 
i. L. compaction , Hook. Old sporangia were observed at the leaf- 
bases, even down to the base of large plants. How early does this 
fertility begin in the individual? 
3. L. Selago , L. There is usually a sterile region at the base of 
the plant : this is followed by the well-known alternating fertile and 
sterile zones. About the limits of these zones, sporangia of smaller 
size are found, which sometimes remain closed when all those in the 
neighbourhood have dehisced. There is no marked change of size 
or form of leaf, on passing from the sterile to the fertile zones. 
Occasionally a single sporangium may be found in an otherwise 
sterile region. 
6. L. erythraeum , Spring. A long sterile basal region is found in 
some specimens. 
1 Monographie des Lycopodiacees, p. 18. 
2 Handbook of the Fern-Allies, 1887, p. 8. 
3 Engler and Prantl, Pflanzenfamilien, i, 4, p. 591. 
