24 FERNS OF KENTUCKY. 
CLASSIFICATION. 
The first systematic arrangement of ferns may be attrib- 
uted to Linnzeus, the great Swedish naturalist, who laid the 
groundwork of our present system, based on the position 
and grouping of the sporangia. ‘The form and arrange- 
ment of the spore-cases, the character of the covering or 
indusium, and the venation of the fronds serve to deter- 
mine the proper methods of classification now in use. 
The earlier systems of classification, though in many re- 
spects imperfect, were generally characterized by a degree 
of accuracy which was very remarkable when we consider 
the limited facilities at hand at that time for making careful 
microscopic investigations into the minute structure of the 
fertilizing organs. Of the thirty genera established by 
Swartz, at the beginning of the century, all but two are 
still retained in the botanical works of the present day. 
The writings of Presl, of the University of Prague, of Sir 
J. E. Smith, of England, of Fée, of Strasburg, and of 
Bernhardi have done much to render the task of classifying 
ferns less difficult for those who have studied the subject in 
modern times. Dr. Mettenius, of Leipsic, and Sir W. J. 
Hooker, of Kew, have given us the latest reliable works 
on the subject of the classification of ferns in general, and 
their systematic arrangement into genera and species. 
In his excellent “’Text-Book of Botany,” Prof. Sachs, of 
the University of Wursburg, makes the following remarks 
on this subject: “The systematic classification of ferns, as 
generally given in the hand-books, is based artificially on 
