90 The Microscope. 



and the soft juicy appearance of the theca3 when 

 unripe, the pretty effect, when, farther on in the year, 

 some will be unripe and pale, some ripe and dark in 

 the same group, and the fairy-like aspect of a group 

 of thecee when they are detached with the cover, and 

 placed in view like a miniature dish of fruit, are all 

 sights sure to gratify the beholder. 



The common Brake fern has its thecse curiously 

 concealed round the edges of the fronds, the margins 

 of which turn down over them. Another little 

 native fern, the Scaly Spleenwort, has its whole 

 stalk as well as the backs of its fronds covered 

 with scales resembling bits of lace ; and the thecse 

 lie thickly between them, like ribbons in the border 

 of a cap. 



The collector of native ferns will naturally feel 

 inclined to examine foreign ones also ; and this can 

 be easily done, as beautiful exotic ferns are in much 

 favour in the conservatory. 



Fig. 9 represents part of the frond of a foreign 

 fern, tha,t known as the Harems-Foot, or Davallia. 

 Its groups of thecse are on the tips of the leaf- 

 lets; the covers are somewhat like little pockets, 

 and, when filled with thecaa, resemble baskets of 

 flowers. 



It will occur to the reader, that there must be a 

 very great number of spores on the fronds of ferns. 

 This is the case ; and in the Hart's-Tongue fern, which 

 has remarkably small spores and thecae, the amount 

 is quite prodigious. Each frond bears on an average 

 80 sori (collections of thecse), containing from 3000 



