THE RUSHES, GRASSES, AND FERNS. 283 



take this elegant little plaint for one of the fern 

 tribe, but a short examination of the spike growing 

 from the single frond will soon convince you of the 

 fact. None of the ferns bear true flowers, although 

 sometimes their superficial appearance warrants the 

 popular belief that some species do. And, as a 

 consequence, they do not bear seeds, but spores, 

 which differ from them in their power of germinating 

 from any part of their surface, whilst a true seed 

 can only sprout from one part. The spores and 

 spore-cases of ferns are among the most beautiful 

 of microscopical objects, and those with which the 

 young microscopist generally makes his first ac- 

 quaintance. The ingenious way with which the 

 halves of the spore-cases are held together by a 

 sort of spiral ring, called the annulus, is very 

 remarkable. Not less interesting and instructive 

 is the different way in which the spore-cases are 

 borne on the backs of the fern-leaves or " fronds." 

 In some, as in the Common Brake, the edges of the 

 leaves are turned over, and thus form the indusium 

 where the spores collect and ripen. In this simple 

 manner we have a differentiation of a part of the 

 leaf taking place when the fern gets riper. The 

 same process occurs in the Common Maiden-Hair 

 fern (Adiantum capillus-veneris] and the following 

 figures show the gradual manner in which this is 

 effected. The spores are contained in little vessels 

 called thecic, which are usually gathered in clusters 

 termed son (No. 3, Fig. 215), the indusium covering 



