112 PEENS OF GREAT BRITAIN. 



tlie driver to convey us to some portion of tlie shores of 

 the lake into which one of the mountain streamlets 

 was continually discharging ; 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, 'Eureka — Eureka!' I hastened onwards, and saw 

 a sight which might have repaid a much more length- 

 ened 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 Eern has a slender creeping horizontal 

 stem, which winds and branches so as to form a net- 

 work 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 



