CHAPTER VII, 
THE FILMY FERNS. 
I. THE TUNBRIDGE FILMY FERN. 
Hymenophyllum tunbridgense. 
* PHE Filmy Ferns form a sort of connecting 
link between the ferns and the mosses. 
They are the tiniest of all the British ferns, 
forming little tufts oftentimes only one inch in 
length ; but sometimes growing to a length of 
six inches. 
The Tunbridge Filmy Fern — so called because 
it was first noticed in the neighbourhood of 
Tunbridge Wells — is a tiny moss-like plant found 
growing on rocks and boulders in the immediate 
vicinity of streams of water. The filmy, pellucid 
texture of the fronds would shrivel up, were the 
plant exposed to dry, hot air. It can only there- 
fore exist in a constant atmosphere of moisture, 
such as is to be found where water is continually 
