172 HISTORY OF BRITISH FERNS. 



cient by wliicli to recognize it, among the refy limited 

 number of kinds which are found in a wild state in Britain, 

 is not its proper distinctive mark. The real characteristics 

 lie in the veins and in the sori. The former may be readily 

 seen by holding a pinnule between the eye and a strong 

 light, and the latter by lifting up the little reflexed lobes 

 which occur here and there at the margin on the under- 

 surface. The veins are dichotomously forked, that is, 

 separating into two equal branches, beginning from the 

 base upwards, the forking being several times repeated, 

 producing close parallel radiating venules which extend 

 to the margin. The sori are produced on the reflexed (or 

 bent-under) membranous expansions of the margin of the 

 fronds, which form the indusia, these indusia being tra- 

 versed by veins which bear the sori. There is only one 

 native species which possesses these characteristics, and 

 this is certainly one of the most beautiful, as it is also one 

 of the rarer of our indigenous Ferns ; and being of small 

 size and of evergreen habit, it is one of the most desirable 

 of all for culture in a "Wardian case. 



The name of the genus comes from the Greek adiantos, 

 which signifies dry, or unmoistened ; and is applicable to 

 these plants, from their possessing in a remarkable degree 



