130 HYMENOPHYLLUM TUNBRIDGENSE. 
HYMENOPHY'LLUM TUNBKIDGE'NSE. 
THIS is popularly called " The Tunbridge Fern" but 
by English herbalists " The Filmy-leaved Fern." It 
was separated from Trichomanes by the late Sir J. 
E. Smith, who erected it into a genus, the striking 
characteristic of which is pointed out by the name 
derived from hymen, a membrane, and phyllon, a leaf. 
The root is wiry, long, slender, smooth, and black, 
creeping extensively upon, rather than within the soil, 
and producing such numerous fibres as to form upon it 
a kind of turf. Fronds solitary, but numerous, rising at 
intervals along the main roots, erect, from one to three 
inches high, smooth, deep green, filmy, semi-transparent, 
curling up as they become dry ; leafleted two-thirds of 
their length ; leaflets alternate, pointing upwards, 
variously lobed ; the lobes narrow and blunt, chiefly 
on the upper side of the leaflet, and their edges toothed. 
The fructification is cup-form, nearly stalkless, at the end 
of a vein, and occupying the place of the lobe nearest 
the main stalk on the edge of a leaflet ; the cover is 
formed by two slightly convex round leafits, equally 
toothed, and folding over each other. 
This Fern is not uncommon in rocky and moun- 
tainous parts of Great Britain, and is there found 
among moss in moist, shady places. It is very plentiful 
on various rocks near Tunbridge Wells ; in Devonshire, 
on rocks at Wistman's Wood, Beckley Fall, Dunsford 
Bridge, and other places ; in Yorkshire, rarely at Green- 
