320 Bower.— Studies in the Phytogeny of the Filicales. 
appendages, of anatomy, of soral construction, and of detail of the sporangia, 
together with certain gametophytic features. The constancy of the parallel- 
ism in features functionally so distinct is held to give just ground for 
drawing the phyletic conclusions sketched above. Further, it has been 
shown that they are in accord with physiological probability, and that the 
fossil record, so far as the known facts bear upon the question, supports the 
phyletic story thus reconstructed. 
Accordingly it is held that in this phylum, which is believed to 
be quite distinct from that of the Ferns with originally marginal sori, 
a progression has been traced which extends from primitive forms showing 
the simple sorus, the protostelic axis, and undivided leaf-trace, to those 
with a mixed sorus, a dictyostelic axis, and highly divided leaf-trace ; 
while in a middle position lie examples with a gradate sorus, and showing 
various conditions of solenostely in the axis, and of subdivision of the 
extended meristele of the petiole. Starting with the ancient Gleichenia- 
ceous type, we have arrived at the Aspidieae as relatively modern represen- 
tatives of the phylum, while the Cyatheaceae and their smaller correlatives 
take a middle position. No attempt has, however, been made here to trace 
critically the ultimate phyletic derivatives of the Aspidieae. This must be 
left over for further investigation. 
The relationships thus recognized have been more or less clearly 
indicated by various systematic writers. What has been attempted here 
has been to widen the scientific basis upon which such conclusions ought to 
be founded. There is accordingly no striking change in nomenclature, 
beyond the upholding of Lophosoria as a substantive genus, quite distinct 
from Alsophila , but related to it. The conclusions arrived at should, how- 
ever, have the effect of recommending a grouping of the families involved 
in their probable phyletic sequence, thus : Gleicheniaceae — Cyatheaceae 
(with minor groups, e. g. Woodsieae, &c.) — Aspidieae. 
DESCRIPTION OF FIGURES IN PLATES XXX-XXXVI. 
Illustrating Professor Bower’s paper on Lophosoria and its relation to other Ferns. 
PLATE XXX. 
Fig. A. Hairs of peculiar form, from the base of the leaf of Gleichenia pectinata . Each hair is 
seated on a massive emergence, from which it is easily detached, the emergence remaining as 
a hard peg-like projection, x 50. 
Fig. B. Part of petiole of Hemitelia horrida, bearing prickles, or peg-like emergences, and upon 
the tip of each is balanced a flattened scale, corresponding to the branched hairs in G. pectinata . 
Slightly enlarged. 
