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36 THE BRITISH FERNS. 
men, are the aim and purpose of study, as some seem to think, 
or to act as if they thought. These are, in fact, but the beginning, 
the very alphabet of inquiry, and are only useful in so far as they 
facilitate the acquisition of real knowledge respecting the structure, 
the habits, the beauties, the properties, the uses, &c., of those por- 
tions of the Creator’s wonderful handiwork which may come under 
observation; in so far, moreover, as they may serve as indices to 
the scattered information which human research has drawn, as 
from a deep unfathomable well, concerning them. This, then, 
is the sense in which nomenclature and arrangement are to be 
understood as important. | 
The characters originally employed in the grouping of F'erns 
into groups.resembling our modern genera, were derived from the 
shape and division of the fronds, but these were found to produce 
very unsatisfactory associations. The generic, or family characters, 
were next sought for in the organs of reproduction. When these © 
came to be adopted, the shape of the sori, or clusters of spore-cases, 
was taken as the most obvious feature; but though affording 
better discriminative marks than the outline and division of the 
frond, the mere form of the sori still proved to be insufficient. The 
presence or absence of an indusium or cover to the sori, and 
the form and attachment of this cover when present, were next 
taken into account; and this combination of characters derived from 
the sori formed the principal advance made up to the early part of 
the present century. Something more was, however, found to be 
required, as the knowledge of species became more extended, and 
this was at length found in the peculiarities of structure presented 
by the venation of the frond, and in the connection of the veins 
with the sori. 
The names of Langsdorf and Fischer, of Brown and of Brongniart, 
the latter in connection chiefly with fossil Ferns, stand pre-eminent 
amongst those who at an early period recognised in these structural 

