258 SOME REMARKS ON THE CLASSIFICATION OF FERNS. 
None of the characters given are at all constant in a number of speci- 
mens from the same locality. 
With regard to habit, on which M. Fée lays perhaps more stress 
than any other author, its extreme diversity in the species of such 
genera as Asplenium and Polypodium seems the most conclusive proof 
of the small value to be assigned it; especially when the differences 
in this respect are by no means eihinident or coextensive with others 
in the venation and the position of the sori. 
I avail myself of the opportunity now afforded to make a few re- 
marks on the ‘Species Filicum ’ of the late Sir W. Hooker, at which 
Mr. Smith has glanced. From the immense materials at the disposal 
of the illustrious author, the labour and care with which it is prepared, 
the fulness of the characters, and the very beautiful and life-like 
figures with which it is so lavishly embellished, this work is incom- 
parably the most important contribution to pteridography which has 
ever appeared. The weak point of the arrangement appears to me to 
be the one which led the late Hon. and Rev. Dean Herbert, thirty 
years ago, in the preliminary treatise to his well-known ‘ Amaryllida- 
ce,’ to direct a most telling criticism against a system of classification 
then recently elaborated by Dr. Lindley ; I mean a want of equality or 
uniformity in the value assigned to characters in the different groups, 
so that some of the genera are scarcely equiponderant with what are, 
in other instances, rated as sections. A lengthened interval elapsed 
between the appearance of the earlier volumes, and in them the genera 
were worked up with extreme care and thought. The recognition of 
ypoderris apart from Woodsia, from which it is only distinguishable 
by habit, of Dictyoriphium (since abandoned by its author, but lately 
restored by Mettenius) apart from Lindsea, of such unstable genera as 
Pellea and Ochropteris, which must surely be absorbed by Cheilanthes 
and Pteris, and of Sadleria, are so many departures from the principles 
expressed or tacitly implied by the author. The two concluding vo- 
lumes were published with unusual rapidity, and bear traces of undue 
haste, and an apparently less vigorous grasp of the subject, doubtless 
attributable to the great age the venerable author had attained. The 
severance of Nephrodium from Aspidium is eminently unnatural, op- 
to the views elsewhere expressed, and based on infinitely less 
satisfactory ground than would have been the admission of Humata 
and Prosaptia, in which the indusia differ far more from those of the 
