122 HISTORY OP BRITISH per:ns. 



affinity. The affinity of the Lady Fern is properly with 

 the Aspleniums, and there is less reason to dispute the 

 conclusions of those who actually place it as a species of 

 Asplenium ; although, as the hippocrcpiform sori indicate 

 a real difference between them, and the genus Asplenium 

 is rather a crowded one, it is a convenience to have them 

 separated. The mark by which the Aspleniums and their 

 allies are known, in addition to the elongated form of the 

 sorus, is its position on the side, not the back, of the 

 veins ; the receptacle being lateral, as it is said. The 

 Athyrimn group is known from Asplenium by having its 

 indusium fringed on the free margin by capillary segments, 

 and by the horseshoe- shaped basal sori ; while in the 

 Asplenium the margin of the indusium is without the 

 membranous fringe, and the sori are not turned back 

 along the reverse side of the vein. There is, as already 

 mentioned, only one indigenous species of Atliyvium. The 

 Asplenium fontcmum is sometimes admitted, but it does 

 not properly belong to this genus. 



The name is derived from the Greek, and comes from 

 athyros, opened ; the allusion being to the position into 

 which the indusium is forced by the swelling spore-cases, 

 bursting out, as it were, like an opened door, after the 



