THE MAIDEN-HAIR FERN. 75 



twice forked, and extend to the margin, where they meet a 

 longitudinal marginal vein which forms the receptacle. 

 The indusium consists of a bleached, membranous, fringed 

 expansion of the upper skin or epidermis of the fronds, which 

 reflexes so as to cover the spore-cases, but there is here 

 another membrane which lies beneath the spore-cases. 



This, which is the most abundant of our indigenous 

 species, is also widely distributed in other parts of the world, 

 and bears a variety of names, from having been supposed to 

 be distinct by those who have met with it from such widely 

 separated localities. 



Being so common, and in an ordinary state uncouth-look- 

 ing, it is not a plant for cultivation to any extent. In warm, 

 clamp, wilderness-scenery, however, where it would attain 

 great luxuriance, and the situation is such as would enable 

 it to develope the arching character already mentioned, it 

 might very properly bo introduced. 



CHAPTER XV. 



THE MAIDEN-HAIR FERN. 



THE Adiantum, or Maiden-hair Fern, may be known by its 

 almost fan-shaped leaflets or pinnules, which are attached by 

 their narrow end to the little black hair-like stalks. This, 

 however, though sufficient by which to recognise it, among 

 the very 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 son. 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 sitrface. The veins are dichotomously forked, 

 that is, separating into two equal branches, beginning from 

 the base upwards, the forking being several times repeated. 

 The sori are produced on the reflexed (or bent under) mem- 

 branous expansions of the margin of the fronds, which form 

 the indusia, these indusia being traversed by veins which 

 bear the sori. There is only one native species whica 

 possesses these characteristics, and this is certainly one of 

 the most beautiful, as it is also one of the rarer of our Ferns : 

 and being of small size and of evergreen habit, it is one oi 

 the most desirable of all for culture in a "Wardian case. 



