TRICHOMANES. 
189 
only in high mountain regions, where they grow from the 
crevices of the moistened rocks. They are both rare, though, 
from the inaccessible localities in which they only occur, 
they may really be more abundant than is generally sup¬ 
posed. Both also appear to be confined to the northern 
parts of our hemisphere. 
Their rarity rather than their beauty invests these plants 
with interest for the cultivator. They require to be kept 
in a cold shady frame, to be potted in porous soil amongst 
lumps of stone, to be carefully guarded against drought or 
stagnant moisture, and to be rarely disturbed at the root. 
Genus XV. TRICHOMANES, or BRISTLE PERN. 
The Trichomanes is the most tropical genus among our 
native Ferns; it is also one of the rarest; the one indi¬ 
genous species being among the few which are met with 
very sparingly, and within a comparatively narrow range. 
It is not, however, the rarest of our species, although very 
unfrequent, and local. Unlike in texture all the other 
native kinds excepting the Hymenophyllums , being quite 
pellucid, and of the most delicately-crisped appearance 
