ONE-SIDED FILMY FERN. \J 



give a veiy incorrect idea of the growing plants. The artist has 

 to show the form of the frond and all its divisions ; and to do 

 this appears to have drawn from flattened dry specimens and 

 has made it appear erect-growing. In reality the fronds lie one 

 over the other, and as they mostly grow on vertical surfaces the 

 tip of the frond is lower than its base. Here the value of a 

 nature photograph comes in to supplement the drawing, for it 

 shows a part of a colony in its natural position and the atti- 

 tude of the fronds when growing, and their relation to the 

 surroundings. 



The Tunbridge Filmy-fern has an extensive, but somewhat 

 peculiar, range in these islands. Its northern limits appear to 

 be Stirling, Mull, and Argyll, from which it extends south as 

 far as West Yorks and South Wales. Then there is a break, 

 but far south it is found sparingly in Kent, Sussex, Somerset, 

 Devon, and Cornwall. In Ireland it is rare, but has been 

 found in counties Clare, Cork, Kilkenny, Connemara, Galway, 

 and Wicklow. It also occurs in the Channel Islands. In 

 vertical range it appears to extend to only 1000 feet above 

 sea-level. 



The popular and scientific names of this fern have reference 

 to the fact that it was first noted as a British species growing 

 in the neighbourhood of Tunbridge Wells. It was formerly 

 known as the Tunbridge Goldilocks. The name of the genus 

 is derived from the Greek utnen, a, membrane, and phyllon, a 

 leaf, in allusion to the filmy character of the frond (Plates 1 1 

 and 12). 



One-sided Filmy-fern (Hymenophyllum unilaterale). 



The One-sided Filmy-fern is even less fern-like than its 

 Tunbridge congener, its fronds lying more depressed and over- 

 lapping, and having a drier and more withered appearance. It 

 does not shun the light so much as the other, and in the 

 Snowdon district we have found large sheets of it extending 



