SOME REMARKS ON THE CLASSIFICATION OF FERNS. 259 
Microlepiee ; and the character relied on seems moreover variable, as 
well as of subordinate value. Nor can the consistency of recognizing 
Fadyenia and Drymoglossum as distinct from Aspidium and Tenitis, 
solely because they have dimorphous fronds, be for a moment defended, 
when it is remembered that Davallia heterophylla, Sm., and D. angus- 
tata, Wall., are retained in that genus, and Hymenostachys combined 
with Trichomanes ; whilst Polypodium biforme, Hook., and P. querci- 
folium, L., might on the same ground equally claim generic rank. 
Vittaria can scarcely be said to have been worked up at all, Fée's mo- 
nograph having been followed, though the genus is so difficult that the 
labours of an independent investigator would have been especially 
welcome. The same may be said of Antrophyum, which does not 
seem separable from Hemionitis ; and the limits between the latter and 
Gymnogramme are not satisfactory. This last-named genus and Acro- 
stichum, as understood by Sir William, seem to include many hetero- 
geneous elements, and certainly require renewed examination and'group- 
ing. The difficulty of properly limiting the genera is unquestionably 
excessive ; but they can scarcely stand as they are, and Platycerium 
seems no more entitled to separation than other sections referred to 
Acrostichum. But, admitting these defects, it may well be doubted if 
any complete view yet given is, as a whole, more natural, with better 
limited groups or fewer weak points ; and, in one most important par- 
icular, the natural grouping and sequence of the species,—an emi- 
nently difficult task,—the arrangement, in the large genera Asplenium, 
Aspidium, and Polypodium, appears to me to contrast very favourably 
with that of Mettenius, in his monograph ; as I think will be admitted 
by any one who will take the pese to dispose a large suite of plants 
according to the views of both w 
Sir William Hooker had arien devoted a greater number of 
years to the special study of Ferns than any either of his predecessors 
or contemporaries. Yet in all his numerous works illustrative of his 
favourite class, there is no more prominent characteristic than the un- 
varying modesty with which his own views, and his dissent from the 
school whose principles diverged so widely from those he held as truth, 
are stated. He repeatedly and ungrudgingly bore testimony to the 
learning, and expressed admiration of the ability, of extreme analytic 
pteridographers, whilst avowing his want of sympathy with their 
opinions; admitting fully that the subject was one on which he put 
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