568 THE FYRN FAMILY. —  [ Woodsia. 
oblong-lanceolate in outline; the longer primary pinnas in the middle of 
the frond, 6 to 9 lines long, the lower ones decreasing ; all pinnate or pin- 
natifid, with small obtuse segments, rather thick, green and glabrous, or 
hairy above, more or less covered underneath with brown scarious scales or 
chaffy hairs. | 
On alpine rocks, in northern and Arctic Europe, Asia, and America, and 
on their great mountain-chains. Rare in Britain, and only in the moun- 
tains of Scotland, northern England and North Wales. Fr. summer. 
W. hyperborea, Br., usually considered as a distinct species, but probably 
only a variety of W. alvensis, differs in its more tender texture, a greener 
colour, the segments shorter and less deeply divided, with more rounded 
lobes, and the scarious scales less numerous, narrower and paler-coloured. 
Its range is nearly the same as that of the ordinary form, but it is 
generally more rare. 
XVI. TRICHOMANES. TRICHOMANES. 
Delicate, half-pellucid Ferns, usually of a dark green. Fructification 
consisting of little cup-shaped involucres, sessile upon or partly immersed 
in the edge itself of the frond. In the centre of the involucre is a little 
bristle, often projecting beyond it, round the base of which are attached the 
minute capsules or spore-cases. 
A large genus, widely spread over the warmer regions of the globe, but 
more especially in tropical America. 
1, T. radicans, Sw. (fig. 1808). European Trichomanes, Bristle 
Fern.—Rootstock creeping, often to a considerable extent. Fronds usually 
6 to 8 inches high, including the rather long stalk ; broadly ovate-lanceolate 
in general outline, twice or thrice pinnate, of a dark green, with rather 
stout stalks and branches. Segments numerous and crowded, thin, pellu- 
cid, oblong, more or less toothed, narrowed at the base. Involucres in the 
axils of the small ultimate segments or lobes, cylindrical, about a line long, 
the central bristle projecting 3 to 1 line more. 
In moist, sheltered, shady places, widely distributed over the tropical 
and hotter regions of both hemispheres, but in Europe only in a few loca- 
lities in western Spain, South Wales, Yorkshire, Argyleshire, and Killarney 
in Ireland. fr. summer. 
XVII. HYMENOPHYLLUM. HYMENOPHYLL. 
Half-pellucid Ferns, closely resembling TZrichomanes, but usually 
smaller; the involucres deeply divided into 2 lobes, and the bristle or 
receptacle usually concealed within them. : 
A large genus, with nearly the same range as 7richomanes. 
1, H. tunbridgense, Linn. (fig. 1309). Tunbridge Hymenophyll, 
Filmy Fern.—Rootstock very slender, creeping, and much branched with 
numerous fronds, forming broad, dense, almost moss-like patches. Fronds 
pinnate, seldom above 2 or 3 inches long, lanceolate in general outline ; the 
stem very slender ; the segments deeply divided into 3 or 8 or more oblong- 
linear lobes, which appear minutely toothed when seen through a lens. 
Involucres at the base of the segments or their lobes, on their inner edge, 
