456 Boodle.—Anatomy of the Hymenophyllaceae. 
the present paper will therefore be chiefly confined to the 
stem and petiole. 
In the nomenclature of the species to be described Hooker 
and Baker’s Synopsis Filicum is followed, and to save repe¬ 
tition the author of a species is generally quoted only the 
first time the species is mentioned. 
The Hymenophyllaceae include, according to Hooker and 
Baker l , the three genera Loxsoma, Br., Hymenophyllum , Linn., 
and Trichomanes , Smith. Of these, Loxsoma is now excluded 
from the order by different authors 2 . Hymenophylhnn and 
Trichomanes have been divided into a number of genera by 
Presl 3 , Prantl 4 and others, on rather small characters, pro¬ 
bably distinguishing sub-genera rather than genera, when 
valid. Hence regarding Loxsoma as excluded, the natural 
order is here taken as comprising only the two genera Hymeno¬ 
phyllum and Trichomanes. 
In the description of structure, Hymenophyllum will be 
taken first, and the observations arranged in sections dealing 
with stem, petiole and node respectively. 
Hymenophyllum, stem. 
The stem in this genus is a creeping rhizome rooted on 
the lower side, and bearing leaves on the upper side, both 
roots and leaves being distichous 5 . It exhibits a consider¬ 
able range of structure, greater complexity occurring in 
species with comparatively stout rhizome and large leaves. 
Hymenophyllum scahrum , A. Rich., has these characters. 
The structure of its mature rhizome is illustrated by Figs, 
i and 4, Plate XXV. Fig. i is a diagram of the entire 
transverse section, in which the parts are distinguished as 
follows:—the outer cortex is left blank, the inner scleren- 
chymatous cortex (sc) is shaded, and the phloem (//^repre¬ 
sented by a ring of broken lines ; the space between the 
1 Hooker and Baker, Synopsis Filicum, 1874. 
3 e. g. Christ, Die Farnkrauter der Erde. 
3 Presl, Hymenophyllaceae, 1843.. 
4 Prantl, 1 . c. 
s Prantl, 1 . c., p= 25. 
