104 



A TEEK BOOK POR EVERYBODY. 



an impression. They delight in clefts and shady nooks, 

 growing on the face of rocks exposed to the spray of water- 

 falls, or dripping with moisture, and even whilst growing 

 look as little like ferns as possible. There are numerous 

 species found in temperate and tropical regions, the East 

 and West Indies, North and South America, Tasmania, 

 and New Zealand. 



The two British species are sometimes fbund growing 

 together, but more commonly in distinct localities. They 

 are very much alike, but are distinguishabl6 by the follow- 

 ing characters : | 



TuraEiDGE Pert^". — Eeceptacle containing the spore- 

 cases flattened, and toothed at the edge. 



"Wilson's Peri^. — Eeceptacle swollen, not flattened, 

 and smooth at the edge. 



TIJNBEIDGE FILMY PEEN.^ 



The rapacity of fern collectors has left vety little of this 

 interesting fern to flourish at Tunbridge Wells, on the 

 old station from whence its name is derived. 



Like its fellow, the black wiry root-stock entwines and 

 forms a dense network over the damp ro(|i on w^hich it 

 flourishes, and from these the filmy fronts rise to the 

 height of 3 or 4 inches, often not much more than 2 inches, 

 in a large dull green patch. The form of thd outline of the 

 frond is almost spear-shaped, with more compound leaflets 

 than in Wilson's Eern : here they are divided and sub- 

 divided so as to resemble branches and bralnchlets of the 

 tough black leaf-stalk, with a narrow band (If filmy green 

 along each side. Tlie receptacles which conliain the spore- 

 cases are urn-shaped, and produced at th^ edges of the 

 fronds. The spore-cases are arranged abiut a central 

 column, which stands up in the receptacle. One point of 

 difference between the Tunbridge Eern and "Wilson's Eern 

 is that in the former, the two portions or valves into 



* Hymenophyllum Ttmbridgense, Sm. 



