THE BRISTLE FERN. 
295 
Nursed in the atmosphere of the waterfall, in that 
atmosphere must it live and develope. 
Rare indeed amongst British Ferns is Tricho- 
. manes radicans. Not England or Wales or 
Scotland can produce it. But it seems to have 
made a home for itself in the south of Ireland. 
There, in many localities, by river-falls, on drip¬ 
ping rocks on the lake borders, in ravines and 
- glens, it is to be found : but only where un¬ 
ceasing dampness, caused by dripping water, 
exists. On the wet surface of the rock or wall 
which it has chosen for its habitat it spreads its 
thread-like, matted roots like a film. Sometimes 
it grows amongst the moss and earth which may 
have collected on the rocks. It has a creeping 
rhizoma, from which grow its fibrous roots that 
cling to the damp rocks or expand in the moist 
crevices between them. The rhizoma is encom¬ 
passed with hairs or bristle-like scales. The 
stem of the frond is usually, but not always, about 
the same length as its leafy part, the shape of 
which, from the point where the rachis com¬ 
mences, is triangular. To the right and to the 
left of the rachis, and extending to the apex of the 
