ON THE GENERA OF FERNS AND THEIR 
CLASSIFICATION. 
rpHE systems for tlie classification of Ferns aro 
almost as numerous as pteridologists themselves; 
indeed, nearly every author, from Linnaeus downwards, 
who has written upon the subject, has propounded his 
own views, and these have generally differed both 
from his predecessors and from his contemporaries. 
But the point upon which pteridologists appear to differ 
most, and on which their only agreement seems to be 
an agreement to differ, is the definition of genera and 
their limits. I say emphatically appear to differ, for 
in the works of those most at issue, the differences are 
not so much in the limits of the groups themselves 
as in the relative importance assigned to them. For 
example, while some, as Presl, Moore, and myself, 
break up the old Linncean genera. Polypodium, Aspi- 
clium, & c., into a greater or lesser number of smaller 
genera, others, as Hooker and Mettenius, prefer ad- 
hering to the Linna?an genera, without greatly altering 
their characters, and adopting the modern generic 
names as sectional ones for such divisions as they find 
themselves compelled to make. It would occupy too 
much space to enter fully upon this subject, and I 
must leave it for a more extensive work upon the 
genera of Ferns, long contemplated by me,* con- 
tenting myself here with a brief mention of the organs 
more or less employed by pteridologists in establish- 
ing and classifying genera. 
* See “Historia Filicum.” — Macmillan & Co. 1S75. 
