44 ° Farmer and Freeman. — - On the Structure and 
characteristic of Neuropteris. This is in striking contrast 
with the venation of Ophioglossum , in which, as is well known, 
the venation is remarkably reticulate. On the other hand' it 
strongly resembles that in Botrychium , which also belongs to 
the same type. Each leaf-lobe in Helminthostachys is traversed 
throughout its length by a stout midrib from which are given 
off on either side, a number of lateral bundles which fork 
once, or sometimes twice, and then run out in an approxi- 
mately parallel fashion to the margin of the leaf. In Botry - 
chium , however, the course of these bundles is not quite so 
markedly parallel, a fact which may perhaps be correlated 
with the more trapezoid form of the pinna. The fact that it 
also recalls the appearance of the venation of Angiopteris , 
may be urged as a ground for not attaching too great 
importance to this similarity in the venation of Helmintho- 
stachys and Botrychium, nor should we have dwelt on it at all 
had it not been supported by many other and, as we think, 
weightier characters. 
The minute structure of the leaf-blade is sufficiently illus- 
trated by the Fig. 18 on PI. XXIII. The cells of the upper 
and lower epidermis both contain chlorophyll, and the stomata 
are confined to, or are at any rate far more abundant on the 
lower than on the upper surface. Each bundle is enclosed 
in a sheath of elongated parenchymatous cells on to which 
the assimilating tissues converge. 
We did not attempt to follow the development of the 
sporangia, as this has been recently done by Bower in his 
monograph on the Ophioglosseae, and our own observations 
do not contribute any new facts to his excellent account. 
The Roots. 
The roots originate from the stem at a very short distance 
behind the apex, and their vascular tissues are united to 
those of the rhizome by a somewhat broad insertion. The 
pith of the root is in connexion with that of the stele of 
the stem, but the communication is not a very direct one, the 
