154 . PLANT-LIFE 



tions; it grows in mosslike patches, and revels in a 

 situation where it is sprayed by the falling waters of a 

 cascade. The uninitiated usually mistake this species 

 for a Moss. The fronds are pinnate, about 2 inches 

 long, with slender stems. The Killarney Fern, Tricho- 

 manes radicans, is found principally in the south of 

 Ireland, in the neighbourhood of waterfalls. The 

 sporangia, in the Hymenophyllaceae, are placed at the 

 margins of the fronds on the free ends of veins. 



2. Polypodiacece. A very numerous division, in- 

 cluding about 3,000 species, all of what may be termed 

 of the " modern " type, being the most specialized of 

 the Ferns. The Male Fern, which we have discussed at 

 some length, is a fair type of the division. The stalked 

 sporangium is a character persistent throughout, but 

 the arrangement of the sori on the back of the fronds 

 is varied in different tribes. Out of this numerous 

 family only about forty species are found in Britain. 

 It is impossible in the space at command to give 

 even the roughest outline of the various tribes and 

 genera. 



Cyatheacece. About 200 species have been distin- 

 guished, none of which are British. These Ferns are 

 of large size, some of them being " Tree-Ferns " attaining 

 a height of between 30 and 40 feet; they occur in the 

 tropics. 



Gleicheniacece. Embraces two genera, Gleichenia and 

 Stromatopteris, the latter having but one species, and 

 the former about twenty-five. They are all tropical 

 and subtropical Ferns. 



Schizceacece. Over sixty species in five genera; 

 nearly all tropical. Includes some small and delicate 



