Cryptogramma (Hooker).—Apparently identical with Allosorus. Exotic
species few in number.
P o l y p o d iu m (Smith).—Margin of the frond flattened, not concealing the
masses of thecæ. British species, 1. V u l g a r e ; 2 . P h e g o p t e r is ;
3. D r y o p t e r i s . Exotic species, very numerous.
W o o d s ia (Smith).—Tliecæ intermixed with bristles supposed to be analogous
to an indusium. British species, 1. I l v e n s is . Exotic
species few in number.
Acrostichum (Bolton).—Veins forming a complex network, whereas, in the
preceding genera, they are never united or connected after
leaving the midvein. Exotic species, l.lieticulatum ; 2 . OUiquum ;
3. Crassifolium, and four others. (Family doubtful.)
F a m il y I I I .—Aspidiaceoe.—Thecæ in a circular mass, covered by an indusium.
C y s t o p t e r i s .—Indusium annexed to the frond at the insertion of the
thecæ, which it contains as in a cup; the unattached margin of
the cup is striated and ragged. British species, I. F r a g i l i s .
Exotic species numerous.
Cistopteris (Hooker)
Cystea (Smith)
Cyclopteris (Gray)
Are identical with Cystopteris.
|ij-
Aspidium (Smith).—Indusium attached by the centre only ; lateral veins
anastomozing, and sometimes forming a complete network.
Exotic species, 1. Trifoliatum; 2. Maorophyllum; 3. Heraclei-
folium, and eleven others.
P o l y s t ic h u m .— Indusium attached by the centre only ; lateral veins never
united after leaving the midvein. British species, 1. A c u l e a t u m ;
2 . L o n c h it i s . ^
Nephrodium (Don).—Indusium reniform ; some, or all of the lateral veins
of each pinnula united to corresponding veins in the adjoining
pinnula. Exotic species, 1. Molle; 2. Unitum ; 3. Arbuscula ;
and about seventeen others.
L a s t r æ a .— Indusium reniform ; veins never uniting after leaving the midvein.
British species, 1. T h e l y p t e r i s ; 2. O r e o p t e r i s , ( I
expect that these two species will be separated as proposed by
Schott, under the names T h e l y p t e r i s Palustris, and T. Oreopteris ;
they difier from the following in bearing the masses of thecæ on
both branches of the lateral veins when they are forked, whereas
the remaining species bear thecæ on the anterior branch only ;)
3. Fmix-MAs ; 4. C r i s t a t a ; 5. R ig id a ; 6. D i l a t a t a . Exotic
species very numerous.
F a m il y IV.—Aspleniaceæ.— Thecæ in an elongate mass, covered by an indusium.
A t h y r iu m (G r a y ) .-Thecæ in elongate-reniform, or sausage-shaped
masses. British species, 1. F i l ix - f e m in a . Exotic species
few in number, mostly included in the genus Allantodia, which is
apparently identical with Athyrium.
A s p l é n iu m (Smith).—Thecæ in elongate and straight masses. British
species, 1. L a n c e o l a t u m ; 2 . A d ia n t u m - n ig r u m ; 3 . R u t a -
m u r a r ia ; 4 . S e p t e n t r io n a l e ; 5 . M a r in u m ; 6 . V i r i d e ;
7 . T r ic h o m a n e s . Exotic species very numerous.
S c o l o p e n d r iu m (Smith).—Thecæ in elongate and straight lines, always in
pairs, the two indusia meeting between them, and at first appearing
but as one indusium, British species, 1 . V u l g a r e , Exotic
species very few.
F a m il y V.—Grammitideæ.—Thecæ in an elongate mass, uncovered by any indusium.
Grammitis (Hooker).—Lateral veins unconnected at their extremities.
Exotic species, 1 . Serrulata ; 2 . Myosuroides ; ,3 . Setosa, and
many others.
C e t e r a c h (Loudon).—Lateral veins anastomozing. British species,
1. O f f ic in a r u m . Exotic species, only one or two known.
S e c t io n II .—F i l ic e s a n n u l a t æ d e s c i s c e n t e s .—Thecæ attached in a receptacle
situated on the margin of the frond.
F a m il y VI.—Hymenophyllaceæ (including the entire section).
T r ic h o m a n e s (Smith).—Marginal receptacle furnished with an exserted
bristle-like appendage. British species, 1. S p e c io s u m . Exotic
species very numerous, and of great beauty.
H y m e n o f h y l l u m (Smith).—Marginal receptacle unfurnished with the bristle-
like appendage. British species, 1 . T u n b r id g e n s e ; 2 . W i l s o n i ;
Exotic species unknown to me.
F IL IC E S EXANNULATÆ.
The thecæ are unprovided with the elastic marginal ring.
F a m il y V II.—Osmundacece Vernation circinate and rachis solid, as in the Filices
annulatæ.
O sm u n d a (Smith).—Thecæ in a branched spike terminating the frond.
British species, 1. R e g a l i s . Exotic species very numerous.
F a m il y V III .—Ophioglossaceee.—Vernation straight, and stem hollow.
B o t r y c h iu m (Smith).—Thecæ in a branched spike attached to a divided
frond. British species, 1. L u n a r ia . Exotic species numerous.
O p h io g l o s s u m (Smith).—Thecæ in a straight club-shaped spike attached
to an undivided frond. British species, 1. V u l g a t u m . Exotic
species few.
The generic and speciflc names printed in small capitals are employed in the
following pages ; those in italics are considered either synonymous or exotic, and are
not employed. The name following the genus is that of a British author who