306 Bower. — Studies in the Phytogeny of the Fili cates. 
Peranema and Diacalpe. 
I have left the detailed examination of these genera to Mr. Davie, 
whose paper on these Ferns precedes this (p. 245 above). I would merely 
remark here that the position which has been assigned to them at the base 
of the Aspidieae appears to be justified on the ground of their dictyostelic 
structure, divided leaf-trace, open venation, abundant chaffy scales, mixed 
sorus, with indusium of the nature of a highly modified scale covering the 
vascular receptacle. Lastly, the sporangia have an annulus, at least partially 
interrupted at the insertion of the stalk, but showing some indications of 
obliquity. These features, combined with the general habit of each, so 
like that of certain types of Nephrodium> indicate a relationship which has 
been already recognized on less extended grounds of observation by 
various writers, and specially by Christ (Farnkrauter, p. 286, and preface, 
p. vii). 
On the other hand, the character of their sorus has from their first 
description been held to relate the Ferns to the Cyatheaceae, and this view 
is stereotyped in the name Peranema cyatheoides , D. Don. Though the 
detail of the correspondence now proves not to be so close as it was earlier 
thought to be, still there is sufficient indication that it is in the neighbour- 
hood of the Cyatheaceae that their natural place is to be found. This 
follows from the position and general character of the sorus, and especially 
of the indusium ; from the vascular receptacle, and from the indications of 
a basipetal sequence in Peranema in the appearance of the sporangia, as 
described by Mr. Davie. But perhaps the most convincing evidence of 
a Cyatheoid affinity lies in those characters of the gametophyte which have 
recently been described for Diacalpe by Schlumberger (‘Flora ’, I9ii,p. 385). 
In the first place, hairs of the Cyatheoid type are present upon its prothallus, 
while further, the lid-cell of the antheridium is divided as it is in the 
Cyatheaceae, but not in the f Polypodiaceae \ These indications, in 
characters which are apparently isolated and not of any great biological 
importance, may on that account be held to be all the more important as 
evidence of the Cyatheoid affinity. 
Woodsia , R. Br. 
This genus was founded by Robert Brown in 1815, and now includes 
twenty-five species, which mostly inhabit cold or temperate zones of the 
Northern Hemisphere, and are of small size. The axis is short and ascend- 
ing, the leaves show an open Pecopterid venation, and the shoot bears 
superficial scales, which are a specially prominent feature in W .polystichoides, 
var. Veitchii. Supplies of this Fern were given from the Edinburgh Botanic 
Garden. The superficial sori have a basal indusium, which is often reduced 
to mere hairs united at their base to form a Cyatheoid cup. The details of 
the indusium are, however, variable in different species. 
