o 
INTRODUCTION. 
The scientific division of the Ferns into tribes and orders was long a deside- 
ratum in botany. The earlier schemes are too vague for the present state of 
science. That of Willdenow, in which he depends upon external characters alone, 
is still, however, used ; it divides the whole Ferns as follows : 
1. Gonopterides, which includes only the genus Equisetum. 
2. Stachyopterides, including Lycopodium, Botrychium, and Ophioglossum. 
3. Schismatopterides, containing only Osmunda. 
4. Filices, which comprises all the Dorsal and Marginal Ferns. 
5. Hydropterides (Water Ferns), containing Isoetes and Pilularia. 
Valuable as the system of Willdenow was, compared to all previously adopted, 
it is very far inferior to that of Sir J. E. Smith, improved as this has been by 
Mr. R. Brown, Kaulfuss, and others. Here, not only the external character of the 
fructification, but the structure of the fruit itself, and of its envelopes, is considered 
of importance as a guide to essential characters ; while the shape, division, and 
habit of the plant, are used only in the discrimination of species : thus classifying 
the Ferns as much as possible by the same laws as those which govern higher 
orders of vegetation. 
FILICALES. 
Leaves never in whorls, with a greatly developed blade, which is usually much 
divided. The theca; at the back or on the margins of the leaves, or on the ribs of 
leaves where the parenchyma is suppressed. Spores of one kind. 
* With their capsules or thecae ringed. 
Theca; in clusters at the back of the leaf, bursting' 
irregularly and transversely. Ring vertical, or a con- > 
tinuation of the footstalk of the theca. Stems solid ; the f 
vernation circinate. 
Thecae on columns contained in little cups on the ’] 
margin of the leaf, bursting irregularly and vertically. I 
Ring oblique. Vernation circinate. Stems solid. J 
POLYPODI ACE.I5 . 
IIymenophyllace.e. 
* * With an imperfect ring to their capsules. 
Thecae in clusters on the metamorphosed terminal ~] 
pinna of a leaf, bursting at a longitudinal suture, two I q 
valved, transparent, stalked, striated. Vernation circinate. [ & 
Stems solid. J 
* * * Without a ring to their capsules. 
Thecae in spikes or racemes formed by the metamor-'] 
phosis of a division of the leaf, bursting at a transverse 
suture, two valved, opaque, sessile, smooth. Vernation 
straight. Stems hollow. J 
>Oph 
iogi.ossaci: !•:. 
EQUISETALES. 
Leaves represented by membranous scales, in whorls forming sheaths round 
the joints of the hollow, furrowed stems. Spores of one kind. 
Thecae in terminal conical catkins. Spores bearing] 
foil! elastic filaments. 
I'.UV I SET ace i:. 
