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have recourse to a system of organs in which the diagnostic characters 
are more strongly pronounced. This is the case in that permanent 
portion of a fern known under the different names of caudex, cormus 
and rhizoma: the roots are almost uniformly fibrous and similar; the 
form of frond is infinitely varied; the caudex possesses an intermediate 
station as to variation, and its variations are such as imply different 
physiological conditions; it is therefore the organ te which the bota- 
nist must look for permanent and obvious differences. It is impos- 
sible to give this organ a careful examination without being struck 
with the fact that it has two totally dissimilar modes of development 
in those plants which are ordinarily called dorsifercus or annulate 
ferns. And here I may as well state that I am not prepared to 
include in my inquiry the genera Schizea, Osmunda, Aneimia, Botry- 
chium or Ophioglossum; these seem to constitute a parallel and 
equivalent series to the true ferns, and a group which I altogether eli- 
minate from the present inquiry. It may possibly be observed that . 
this is an incongruous series, its constituent members being iso- 
lated, and the whole group resembling a miscellaneous assemblage of 
individuals huddled together by chance; but to me they possess a far 
higher interest than this, a far greater value in the universal system: 
they appear as the remains of an earlier creation, the extinct members 
of which have been photographed on stone, the impressions alone 
remaining to assure us that such things were. Mertensia, Gleiche- 
nia and Danza occupy very debateable ground; and without a far 
more intimate knowledge of them than I have the means of acquiring 
their true posilion must remain a mere matter of speculation. 
The two modes of growth are so well distinguished by Mr. Smith, 
in the passage already cited, that little remains to be added. For the 
sake of precision I will recite the chief diagnostics :— 
Ist, I call by the name of Rhizophyllacez all those ferns which 
possess a succulent, creeping rhizome, the growing extremity of 
which never eventuates in a frond; and, 
2nd, Cormophyilacee, all those which possess an erect or prostrate 
caudex, the growing extremity of which always eventuates in fronds. 
Order RHIZOPHYLLACEZ. 
In the Rhizophyllacee the rhizome is generally densely clothed 
with scales; it produces fronds at every point of its surface, except 
ihe growing extremity; these fronds appear at first on the surface of 
the rhizome, as minute excrescences, displacing a portion of the scaly 
covering; they are always sclitary, always of very slow evolution, and 
