238 Bower . — Imperfect Sporangia in certain 
General theoretical position based on comparison 
OF THE GENUS LYCOPODIUM, AS REGARDS DISTRIBU- 
TION of Sporangia. 
The theoretical bearing of such facts as the recurrence of 
sterile and fertile zones in certain Lycopods, and the existence 
of abortive sporangia at the limits of the fertile zones, was 
pointed out in the first part of my studies 1 , and again in 
a later paper in the Annals 2 . The facts being now amplified 
by examination of a larger number of species, and of speci- 
mens, the conclusions which may be drawn will be stated in 
an extended form. 
First it will be well to re-examine the theoretical position 
as regards abortive parts generally. It is possible to look 
upon any imperfectly developed part as either in the up-grade 
of development — as something nascent ; or in the down-grade 
of development — as something evanescent ; and these ideas 
themselves may be applied in either of two senses, according 
as they are taken to refer to the individual or to the race. 
There are thus four possible views which may be taken of 
any imperfectly developed part : — 
(1) that it is nascent in the ontogeny ; 
(2) that it is evanescent in the ontogeny ; 
(3) that it is nascent in the phytogeny ; 
(4) that it is evanescent in the phytogeny. 
These distinctions may not be admitted by those who 
assume that the ontogeny is a direct and complete index 
of the phylogeny, that the parts first formed in the individual 
were also the first to appear in the evolution of the race. 
This 5 recapitulation theory 9 may be consistently entertained 
for the sporophyte by those who hold that the alternating 
generations of the Archegoniatae originated by differentiation 
of homologous phases 3 : to them the view is possible, though 
I am not aware of its having been definitely expressed, that 
spore-production may have been in the evolution a sort of 
1 Phil. Trans., 1894, B., p. 535. 2 Annals of Botany, vol. viii, p. 343. 
3 See Scott, Presidential address to Sec. K, Brit. Assn. Report, 1896, p. 996; 
where the necessary literature is quoted. 
