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Douglas Houghton Campbell. 
As one of the botanists who believe that the Hepaticae form a 
very important link in the evolutionary series leading up to the 
higher plants and are really ancient types, the writer has thought it 
worth while to call attention to certain facts that have not received 
much attention, and that may have a bearing upon the question of 
the antiquity of the Bryophytes. 
The presence of impressions from palaeozoic rocks, which there 
seems no good reason to doubt belong to genuine Marchantiaceae, 
are cited by Dr. Scott; and of the mosses the fossil Musettes 
polytrichaceus, Renault and Zeiller, seems to be generally admitted 
to be a true moss. Both of these belong to the more specialized 
types, and admitting that they are correctly identified, they must 
have been preceded by a long series of simpler forms. 
While it is true that very delicate tissues have been preserved 
in a fossil condition in some Pteridophytes, in most cases, at least, 
these are protected by a covering of more resistant tissues, as in the 
delicate parenchyma of stems, or the tissues within sporangia and 
seeds. The hyphze of Fungi, also, that are known in a fossil 
condition, are protected within the tissues of other plants. The 
tissues of all Hepaticae are excessively delicate and perishable, and 
the resistant parts such as the elaters are of microscopic dimensions 
and would certainly be overlooked unless very careful search was 
made for them. It may very well he that a rigid examination of 
sections of the masses of petrified material might reveal traces of 
elaters; or evidences of epiphyllous species, such as are so common 
at present in wet tropical forests, might reward a careful study of 
the surface of the fern leaves that are so abundant in the palaeozoic 
rocks. 
It is not strange that the study of the vascular plants has 
largely monopolized the attention of students of palaeozoic botany ; 
but until one can be sure that the same exhaustive methods have 
been used in the search for bryophytic remains that have 
characterized the study of the vascular plants, one may be pardoned 
for maintaining a somewhat sceptical attitude in regard to the 
assumed unimportance of Bryophytes in the palaeozoic flora. 
The remains of Bryophytes are almost as scarce in the later 
formations, except for the interesting forms found in amber (Rngler 
and Prantl—1 Th., 3 Abt., p. 134.) The latter are too recent to 
throw much light on the question, and are all very close to living 
genera. 
It must be admitted, then, that our present knowledge of the fossil 
