192 



THE SWAN AND HER CREW. 



provided for the production of the spores, and these mostly 

 differ in shape from the ordinary or barren fronds. 



The spore-cases are generally almost microscopic, flask-like 

 in shape, and encircled by an elastic ring of peculiar structure, 

 which passes either from top to bottom like a parallel of longi- 

 tude, or round the sides like the equator round the earth. The 

 exact nature of this band, whether its elasticity be due to the 

 mechanical arrangement of its cells, which are narrower on 

 the inner than on the outer side, and apparently filled with 

 solid matter, or to a quality of its substance, I am unable 

 to determine. 



WILSON'S FILMY-FERN. 



TUNBRIDGE FILMY-FERN. 



When the spores are fully ripe, and ready for dispersion, the 

 band, which has hitherto been bent around them, springs open 

 with great suddenness and force, tearing the enclosing mem- 

 brane and casting them forth upon the breeze, to undergo in 

 their turn all the changes we have traced, or, as must be the 

 case with multitudes, such are the countless numbers in which 

 they are produced, to perish, humanly speaking, with all the 

 beautiful possibilities of their nature for ever lost. 



The botanist is led away from care, not merely into holes 

 and corners 



" Brimful dykes and marshes dank " 



