ASPLENIUM. 81 



This is rather a diminutive plant, but, when in a vigorous 

 state, has a very interesting appearance, from the contrast 

 between its black stipes and rachis, and the bright green 

 pinnae, and from the regularity with which the latter are 

 disposed. It grows in tufts, naturally introducing itself 

 into the joints of old masonry and among the crevices of 

 rocks, and producing numerous small slender fronds, of a 

 linear form, in its most vigorous state nearly a foot long, 

 but generally from three to six inches. They are evergreen, 

 simply pinnate, on a rather short stipes, which is of a 

 purplish-black, the rachis also being of the same dark 

 colour. The pinnae are dull green, small and numerous, 

 equal-sized, of a roundish-oblong figure, attached to the 

 rachis by a stalk-like projection of their posterior base ; 

 the margin is rather entire or crenated. The pinnae are 

 jointed to the rachis, and when old are readily displaced, so 

 that eventually the black rachis is left denuded among the 

 tuft of fronds. 



A distinct midvein passes through each pinna, giving off 

 on each side a series of venules bearing veinlets, the an- 

 terior of these producing the linear sorus just within the 

 margin of the pinnae. The sori, which in the young state 

 are covered by a thin indusium having a somewhat crenu- 



G 



