BRITISH FERNS. 



93 



Hymenophyllum Tunbridgense is a native of the southern 

 counties of England. I have seen numberless specimens from 

 Kent and Sussex, and I am told by different botanists of its 

 occurrence in Cornwall, Devonshire, Somersetsliire, and Glamor- 

 ganshire ; but as I have seen no specimen from these counties, and 

 am therefore uncertain as to the species, I have refrained from 

 assigning these habitats to either. In the south and v^est of 

 Ireland, Tunbridgense appears to be very abimdant, I have 

 found it clothing the rocks about Killarney in very great 

 beauty and profusion. 



The roots are black, wiry, and very slender; the rhizoma 

 long, black, slender, wiry, and creeping. The fronds consist of 

 a branched series of veins, each being clothed with a membranous 

 or filmy wing, as in Trichomanes : the branches or pinnae are 

 alternate, and each more or less subdivided ; the subdivisions 

 or pinnulae are mostly in pairs : the margin of the wing is 

 crenated, and very minutely spiny : the masses of thecae are in 

 flat marginal receptacles, situated at the union of the pinnae 

 with the rachis : in this species these receptacles have a serrated 

 external margin. 



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