158 BOTANICAL GAZETTE | SEPTEMBER 
tion of the megaspore, which still develops its exine in Cor- 
daites and some cycads. 
As to the pteridophyte group from which the Cordaites were 
derived, data are not sufficient to make opinion other than a 
pure hypothesis. I think it is clear that such heterosporous 
pteridophytes as are living today must be set aside in this 
search, by the testimony of both of their gametophytes, espe- 
cially the male. They stand for lines which have very much 
reduced the male gametophyte, have variously modified the 
female gametophyte, but have not developed siphonogamy by 
retaining the megaspore. It may be that the lycopod forms of 
the Carboniferous and earlier formations represent the pterido- 
phyte plexus from which Cordaites were derived, but we know 
too little of their morphology to make any assertion. My judg- 
ment is that the Cordaites represent an independent hetero- 
sporous line, and that if they were associated in origin with the 
lycopod forms at all, it was before the latter had developed 
heterospory, which seems never to have been extensively devel- 
oped in the lycopod line until recent times. 
I believe that we must regard either the ancient homosporous 
lycopod forms or the abundant Paleozoic Marattia forms as 
responsible for the origin of Cordaites, and my own inclination 
is toward their Marattia origin, perhaps for no better reason than 
that in such an origin I see more opportunity for the develop- 
ment of such a group as cycads; but such a view is further sup- 
ported by the discovery that the spermatozoids of cycads, and 
their ally, the ginkgo, are of the multiciliate type, and not bicil- 
iate, as in living lycopod forms. Just what stress should be 
laid upon this I do not know, but when opinion is fairly balanced 
it would seem to help to a decision. It seems satisfactory, 
therefore, to regard the origin of cycads as from the homospor 
ous-eusporangiate plexus of Filicales, represented today most 
abundantly by Marattia and its allies. It would seem further 
that this has been brought about without the intervention of 
such Cordaites as we recognize, which, with probably similar 
origin, were developing a very different type of body, that 
