TRICHOMANES. 
183 
form a curtain of net- work over the rock; the stems 
occupy about one-third the length of the frond, and have 
wings of the same substance 
as the leaflets. The frond 
is oval in form, varying to 
triangular, its substance re- 
sembles that of a seaweed, thin 
and transparent. Each pinna 
is furnished with many pin- 
nules, which in their turn are 
divided into leaflets with three 
or more lobes, a mid-vein 
running through the leaflet 
sends a branch into each lobe, 
and one branch passes beyond 
the leaflet, the sori cluster 
round its base, and an urn- 
like involucre forms outside them, leaving the bristle- 
point of the vein naked ; this forms the distinguishing 
feature in the family. 
To see this plant in its full beauty we must visit Ire- 
land and gaze on the waterfalls of Wicklow, Kerry, and 
Killarney, where the fern grows in curtains of verdure, 
every frond shining with the diamonds of the spray. 
The delicate texture of the fern possesses a wonderful 
power of revivification, and may be freshened after being 
dry for years, by immersion in water. 
It has been found in one or two places in Yorkshire, 
but has of late been sought there in vain. But we learn 
from the Botanical Staff at the British Museum that it 
has been found recently in Wales, and in the Isle of 
Arran, off the coast of Galway. It is evergreen ; young 
fronds appear in May, but do not expand till autumn. 
