more Kable to become injured and broken than such as are
fastened to the paper.
The specimens should be fully labelled, the labels giving
at least their names, the locahty where gathered, and the
date; and these labels should, as far as possible, be fixed
with some degree of uniformity as to their position, so as to
be readily referred to by turning up one of the corners of
the sheets of paper.
The papers to which the specimens are affixed should be
enclosed in paper covers, each genus separately; and these
covers should be placed either on the shelves of a cabinet,
or in drawers, or in any convenient place where they may
be preserved against dust, the attacks of insects, and other
casualties.
THE CLASSIFICATION OF FERNS.
T h e first notions of classifying the Eerns, if we may judge
from the Latin sentences which served as names for them in
former times, were derived chiefly from the size, form, and
general resemblance of the fronds, and the situations in
which they grew. As, however, the knowledge of their
structure and organization became extended, the insufficiency
of such means of distinction and arrangement became apparent
j and when the great Swedish botanist, Linnaeus, set
about the task of distributing the plants known to him, into
family groups, he selected the fructification as the leading
character of association, his groups of Eerns being formed
from the resemblances in the form and position of the
clusters of ' seed-vessels,’ which we have already mentioned
(p. 17), under the name of spore-cases.
Those who immediately succeeded him did but carry out
to greater perfection, in accordance with increasing knowledge,
the same general idea of family relationship, the most
important additional characteristic called into requisition
being that derived from the presence or absence of a general