251 SOME REMARKS ON THE CLASSIFICATION OF FERNS. 
maria, and the whole of Blechnum are of the same lineage, and quite 
unconnected with Gymnogramme.” Now, there is here a singular 
confusion of ideas. After recognizing the ** parallelism” of Sadleria 
and Brainea in one sentence, Mr. Smith proceeds in the next to place 
the two together, as of the same lineage ; that is to say, he very evi- 
dently confounds analogy with affinity. With respect to the relation- 
ship which Mr. Smith insists to be so manifest and easy of recognition, 
the obvious reply is, that neither Professor Mettenius nor the late Sir 
William Hooker perceived it ; and I may be allowed to say that I feel 
an equal inability. Mr. Smith further writes :—“ If the Darwinian 
theory of the origin of what is called species from antecedent species 
be admitted as a guide to assist in determining affinity, then the 
Cycad-looking stem of Brainea should be compared with that of 
humble Gymnograms.” If I apprehend rightly Mr. Smith’s meaning 
in these words, it is that nearly-allied genera should agree in habit; 
and, that the arborescent caudex of Brainea is a fatal objection to its 
close alliance with Gymnogramme. Though not myself, by any means, 
a decided opponent of the remarkable theory which, through the learn- 
ing, the unrivalled power of illustration, and the rare and scrupulous 
candour of Mr. Darwin, has made so deep an impression on all 
thoughtful students of natural science, I might object to the petitio 
principii involved in assuming a very generally disputed hypothesis as 
the basis of an argument ; but, in cases where numerous facts contra- 
dict the presumption expressed, we may safely keep to the facts, and 
leave theories aside. I do not myself see that Woodwardia radicans, 
Sw., Lomaria Spicant, Desv., Blechnum lanceola, Sw., or any species of 
Doodya, can in any sense be called less humble than such Ferns as 
Gymnogramme japonica, Desv., G. javanica, Bl., or G. trifoliata, Desv. ; 
or less dissimilar in habit to vedas: by the side of which Mr. Smith 
ranges them. And, amongst flowering plants, in such a truly natural 
genus as Euphorbia, to give an example, it is only necessary to advert 
to such species as Z. neriifolia, L., E. tirucalli, L., E. palustris, L., 
and Æ. thymifolia, Burm. ; or, in the order Urticacee, to such a plant 
as Laportea gigas, Wedd., as compared with Z. Canadensis, L., or L. 
bulbifera, S. and Z., to iow how destitute of foundation is the as- 
sumed test; since bai it is allied species which differ in habit more 
than many allied genera. T cannot assent to Mr. Smith's opinion that 
the absence of an indusium in Brainea is of no weight against his view 
