Bower.—Studies in the Phytogeny of the Filicales. 425 
Plagiogyria were not only the oblique annulus, but also certain peculiarities 
of the vegetative organs (1. c., p. 7), such as the swelling of the leaf-bases, 
the spongy tissues (aerophorae) which they bear, and the absence of peltate 
scales ; also he notes that the spores are tetrahedral. This monograph, to 
which allusion will frequently be made below, gives by far the most 
complete account yet published of this interesting type of Ferns. Later 
writers seem to have left the genus severely alone, so far as detailed in¬ 
vestigation is concerned. Prantl 1 does not even mention it in his valuable 
remarks on the systematic importance of the annulus, nor does he place 
the genus by name in his system of the Polypodiaceae. Of later writers 
Diels 2 places Plagiogyria as a substantive genus under the Pterideae, and 
in next proximity to Cryptogramnie. Christ 3 also maintains it as a sub¬ 
stantive genus ; he places it at the end of the Pterideae (Hook.), and next 
to Actiniopteris , with Blechnum as the first genus of the succeeding Blechneae. 
Raciborski, 4 on the other hand, follows Hooker’s ‘ Synopsis ’ in still including 
the species under Lomaria. 
It is quite plain from the above notes that the Ferns now grouped in 
the genus Plagiogyria occupy an anomalous position in the whole system ; 
moreover, the knowledge of their characters is still very incomplete; the 
prothallus has never yet been described, and the anatomy is still very 
imperfectly known. It thus appears desirable to submit them to a fresh 
examination, with the object of widening the basis of their comparison with 
other forms. More especially does this seem necessary in view of the fact 
that Plagiogyria alone of described Ferns appears to combine the distinctly 
oblique annulus of some Simplices and of the Gradatae with certain general 
characters of the Mixtae. It will be seen later that this conjunction of 
features usually distinct gives the genus a special importance in estimating 
the probable phyletic relations of the Mixtae to other relatively primitive 
types of Ferns. 
As at present described, there are eleven species of the genus Plagio¬ 
gyria ; two of these inhabit the Western hemisphere, and one of them, viz. 
P. semicordata , (Pr.) Christ, was collected on Sir John Peak, on my recent 
visit to Jamaica ; living plants and fresh spores were brought to Glasgow, 
as well as dry specimens and preserved material. The remaining nine 
species are Eastern, being chiefly represented in China and Japan ; the 
material available was referred to P. pycnophylla , (Kze.) Mett., a species 
native in the north of Hindustan, the Malay Peninsula, and in Java ; it was 
derived partly from Darjeeling, from Mr. Hemsley, and largely from 
Buitenzorg through the kindness of Dr. M. Treub. From the same source 
1 Das System d. Fame. Arb. aus dem k. bot. Gait, zu Breslau, i, p. 4. 
2 Engler und Prantl: Pflanzenfam., i. 4, p. 281. 
3 Farrnkrauter der Erde, p. 175. 
4 Die Pteridophyten der Flora von Buitenzorg, p. 162. 
