Pteridophytes . Are they vestigial? 227 
the abortive ovules in the carpels of the Clematideae may 
be mentioned ; though in the mature state only one ovule is 
found fully developed in each carpel, several are initiated in 
position corresponding to those of the Helleboreae ; on these 
facts the argument may be based that a plurality of ovules 
was more widely the rule in the ancestors of the Ranuncu- 
laceae than it is at the present day 1 . A similar case as 
regards the pollen-sacs is found in the stamens of Salvia . 
There is thus no reason to restrict the method to axes, leaves, 
and so forth, but it may be, and has been, applied to spo- 
rangia equally with other parts. 
In the Pteridophytes, too little attention has hitherto been 
paid to such subjects, and notably observations of arrest of 
the spore-producing parts have been neglected. It is the 
comparative isolation of many of the genera, and the paucity 
of species in some of the most important of them, which has 
stood in the way of arguments from arrest taking their proper 
place in the morphology of the Pteridophyta. But the 
argument to be based on an imperfect sporangium of Lyco- 
podium, or the abortive fertile spike of an Opkioglossum, 
seated in the position normal in other individuals, species, or 
allied genera, for a fully matured one, is precisely the same 
as that on an imperfect stamen or carpel, pollen-sac, or ovule. 
Further, a comparison as regards the presence or absence 
of spore-producing parts, in species evidently related to one 
another, may lead to the conclusion that sporangia, entirely 
unrepresented at the present day^ were probably present in 
the ancestry ; the line of argument being the same as that 
in the cases of hypothetical ‘ ablast,’ or complete suppression 
of floral parts. 
In this paper I propose to bring together certain cases of 
incompletely developed sporangia, or spore-producing parts 
in the Pteridophyta, in order that those facts may have their 
due weight in the general discussion of the balance of the 
vegetative and fertile regions of the primitive leafy sporo- 
1 Eichler, Bluthendiagramme, p. 174 ; also Prantl, Engler’s Jahrbiicher, vol. ix, 
p. 237. 
