CHAPTER VII. 



PELL^A, Link. 

 (Pel'-W) 

 Cliff Brake Ferns. 



HE name of this genus is derived from pellos, dark-coloured, in 

 reference to the dusky colour of the fronds of certain species. 

 Pellasas, which in Hooker and Baker's "Synopsis Filicum" 

 form Grenus 30, may be considered an important and very 

 interesting section of the tribe Pteridece. In habit of growth, 

 as also in geographical distribution, they are closely allied to Cheilanthes, from 

 which they differ principally through the continuous nature of their involucre 

 (covering of the spore masses). The distinguishing characters of the plants 

 belonging to this genus reside in the disposition of the sori (spore masses), 

 which are intramarginal (within the margin), terminal on the veins, which in 

 nearly all cases are free, at first dot-like or decurrent on the veins, but soon 

 running into a line ; also in the character of the involucre, which is formed 

 of the more or less changed edge of the frond, quite continuous and sometimes 

 very narrow. This genus is widely distributed and comprises about sixty 

 species of stove and greenhouse Ferns ; but it has no British representative. 

 According to the presence or absence of various distinctive characters, Pellcea 

 has been subdivided into four sections as follow : 



Allosorus ( All-os-o'-rus), Presl. The plants of this section have fronds 

 of a leathery texture, in which the veins are not perceptible. The ultimate 

 segments of the frond are at least twice as long as broad, often revolute at 

 the margin, and the involucre is broad and conspicuous. One of the species 



