MARSH FERN. 



LASTR^EA THELYPTERIS. Presl. 



Thelypteris palustris. S chott. 



Aspidium palustre. Gray. 



Aspidium Thelypteris. Swartz, Smith, Hooker, Galpine, Mackay, 



Francis. 



Acrostichum Thelypteris. Linneus, Bolton. 

 Polypodium Thelypteris. Withering, Berkenhout, Lightfoot, 



Hudson, (his specimen in the Smithian Herbarium is undoubt- 



edly correctly named Thelypteris.) 



LOCALITIES. 



ENGLAND ... Northumberland, Learmouth Bogs, near Cornhill; Cheshire, from various 

 localities, without further particulars; Cambridgeshire, Whittlesea Mere; 

 Norfolk, Filsby, Ormsby, Bolton Bay, Horning Marshes ; Kent, Ham Pond, near 

 Sandwich, in the marshy meadows, and filling the wood to the exclusion of other 

 ferns ; Isle of Wight, marsh near Freshwater gate. 



"*"- 

 IRELAND .... County Antrim, near the north-east coast of Lough Neagh. 



LASTR^A THELYPTERIS, the Marsh Fern, is one of our rarest 

 or, rather, our most local species : it is so commonly confounded 

 with Oreopteris, that the localities usually given for either 

 are of but little value : each of those recorded above may be 

 strictly depended on. In England it appears widely distributed, 

 and in Wales I think it has occurred in several unrecorded spots* 

 In Ireland I believe it has only been found in the banks of 

 Lough Neagh, by Mr. Moore, of the Glasnevin Botanic Garden ; 

 and in Scotland, to the best of my belief, it is at present totally 

 unknown. It is only found in wet and marshy ground, where its 

 black, slender, and wiry rhizoma, can creep to any extent without 

 impediment from the substance of the soil ; its roots are black, 

 fibrous, and, in some instances, very long ; they appear to 



