241 
Pteridophytes. Are they vestigial? 
definitely nutritive in function 1 : the strobilus with the 
sporogonium : the abortive sporangia at the base with the 
arrested archesporial region at the base of the capsule : 
the abortive sporangia so commonly found at the apex of 
the strobilus with the arrested archesporial region, which 
passes upwards into the operculum. There is first in each 
case a vegetative phase, which is nutritive ; this merges into 
a fertile phase, which again is arrested above, being probably 
in each case limited by nutritive supply. On the antithetic 
theory, in either case the spore-production was the prior 
function in the race ; in either case that function was delayed 
in the individual by a later intercalated vegetative phase. 
The prevailing view which regards the evolution of the 
sporophyte in the two great series of the Archegoniatae as 
following from the very first a distinct course of development 
is probably correct, in the sense that specialized Bryophyte 
sporogonia did not give rise to Pteridophyta ; but the analogies 
as regards balance of the vegetative and spore-bearing phases 
should not be lost sight of, on the superficial ground that 
appendicular organs are present in the one and not in the 
other. For both series have equally been subject to the 
fundamental laws of nutrition, which have dictated these 
successive phases. 
Our first duty will then be to interpret those parts which 
are found about the transition from the vegetative to the 
fertile region in Lycopodium , and see what bearing they may 
have on our views of the origin of the vegetative region in 
that genus. But in doing so we shall start with the clear 
understanding that though certain parts are formed first in the 
1 It seems hardly necessary to state that no exact morphological homology is 
here implied, but merely a comparison of the successive phases of nutrition and 
spore-formation. The specialized sporogonium of a Moss is not looked upon as 
the progenitor of any race of vascular plants. As I have been credited in various 
quarters, and on insufficient grounds, sometimes quite misunderstood, with the 
opinion that a Moss sporogonium was the source from which a leafy sporophyte 
originated, I wish to expressly disown such an opinion. A parallelism in method 
of morphological advance may be traced, without any recognition, in such series 
as show it, of -any true affinity. 
