Pteridophytes. Are they vestigial? 265 
Following then the methods of comparative study of Bryo- 
phytes and of Angiosperms, and employing them upon the 
results yielded by specific study of the genus Lycopodium , 
there seems only one reasonable reading of the facts : that 
sporangia, previously in the race fully formed, have become 
abortive; either partially, so as to leave vestigial traces, or 
entirely : that sporophylls have thus passed to the condition 
of foliage leaves : and that thereby the vegetative system has 
been increased. There seems further a reasonable probability 
that, in Lycopodium at least, the whole of the foliar system 
may have originated in this way \ 
It was remarked above that the general line of argument in 
this paper would follow naturally, perhaps we may even say 
necessarily, from the acceptance of the theory of antithetic 
alternation. But it is also consistent with the view that the 
alternating generations are really homologous, if spore-pro- 
duction appeared early in the history of the neutral genera- 
tion 1 2 : and this it must certainly have done, if the earliest 
sporophytes were like those simpler ones we see at the present 
day. Comparison leads decisively to the conclusion that the 
formation of spores was not a happy after-thought, imposed 
upon an already present and extensive vegetative system, but 
of early occurrence in the primitive individual. It may or 
1 This idea has already been put forward by Naegeli in the following sentences 
(Abstammungslehre, p. 477) : c Die zweite Stufe ist also ein unverzweigter beblat- 
terter Stengel ; die noch hochst einfach gestalteten Blatter sind alle gleich und 
sporogonientragend : in der Abstammungslinie der Lycopodiaceen mag diese 
Stufe grosse Aehnlichkeit mit einem unverzweigten Lycopodium Selago gehabt 
haben.’ Though I should not subscribe to the exact mode of origin of such a 
form suggested by Naegeli, it is to be remarked that he clearly contemplated an 
organism in which all the leaves are originally sporophylls, and that the vegeta- 
tive system originated by deferring the spore-production to later stages of the 
individual. The presence of the imperfect sporangia at the base of the fertile 
region in so many Lycopods supplies important evidence from vestigial organs, 
which coming after the enunciation of his views based on other grounds, is a very 
strong support of them. 
2 Compare Coulter, Origin of the leafy Sporophyte, Bot. Gaz., 1899, P* 46. 
He suggests a possible antithetic origin in Bryophytes, and homologous for Pterido- 
phytes ; in the latter case he supposes a leafy axis bearing spores, derived from the 
thallus (p. 55). 
