152 FILICES 
the lake into which one of the mountain streamlets was continually dis- 
charging, well knowing that, in the course of such a rill from the mountain- 
top, there would occur many places suited to the growth of this moisture- 
loving plant. We were landed accordingly on the south side of the lake, 
amid a mass of osmunda, and after making our way up the stream a few 
hundred yards, surrounded by masses of rocks confusedly hurled, and coated 
with fine hymenophyllum, and various mosses and liverwort, Dr. Harvey, 
who was in advance, called out, ‘Kureka—Eureka! I hastened onwards, 
and saw a sight which might have repaid a much more lengthened and 
laborious search. In the inside of a natural cave, about five feet square, 
formed by four large masses of limestone, the Trichomanes was growing in 
its native beauty. One specimen, with a creeping rhizome three or four 
feet in length, and containing forty-eight perfect fronds, we divided, and 
my portion is now in the hands of your artist. The mouth of the cave 
faced the north, so that not a ray of solar light ever reached the plant 
within ; and to this cause I attribute the total absence of fructification on 
any one of the specimens.” 
The Bristle Fern has a slender creeping horizontal stem, which winds and 
branches so as to form a network over the rock, and is covered with black 
down. This woolly substance has been found by Mr. Andrews, when viewed 
under a lens of high power, to consist of articulated bristles, analogous to the 
scales on the stems of other ferns. The whole frond is so pellucid, the veins 
so prominent, and the green part so like a membranous wing around the 
veins, that it has more the appearance of a sea-weed than a fern. ‘The frond 
is between lanceolate and triangular in form, the divisions being so much 
waved as to give it a crisped appearance. It is three or four times pinnatifid, 
and the slender segments of which it is composed are either entire or two- 
cleft at the apex, and a strongly-marked and stout vein runs up the centre. 
Indeed, the veins are so prominent and rigid, that they seem the most con- 
spicuous part of the fern, and the frond might very well be said to consist of 
a number of firm veins, three or four times branched, and edged by a thin 
green membrane-like wing. Some of the terminations of the veins are sur- 
rounded by the green part, which forms a little cup in which lie the capsules 
of fructification. The involucre, as this is usually called, most commonly 
projects beyond the margin of the frond, but it sometimes lies within it, and 
the bristle is often four or five times the length of the cup, though in many 
cases scarcely exceeding it in length. The fronds are from three inches to a 
foot long, and mostly droop over the sides of the rocks. Though appearing 
in May, they are not matured till about November, nor do they attain their 
whole size or bear their fructification until the third year of their growth. 
Now that it is discovered to thrive so well in the closed cases, this plant is a 
favourite subject of the cultivator’s care. It requires a pure and constantly 
humid atmosphere, shade and warmth, and these conditions can all be given 
by the glass case. It may be grown also in an earthen pot standing in water, 
and covered with a bell-glass. A variety of this fern, of broader lanceolate, 
somewhat egg-shaped form, has been termed andrewsii, after its discoverer ; 
it is found at Kerry. The Bristle Fern is by various writers called Trichd- 
manes brevisétum, specidsum, and Hymenophyllum alatum. 
