226 



BLACK SPLEENWOBT. 



opinion, the name of Asplenium Adiantum-nigrum being as- 

 signed to it by general consent. 



It has been found in every country of Europe, in North and 

 South Africa, in Madeira, Teneriffe, and many other Atlantic 

 Islands. A species very similar to the common EngUsh form 

 of this plant has been discovered in the United States, but is 

 of such great rarity that the opportunity of forming an opinion 

 on the subject, from a careful comparison of a sufficient num- 

 ber of specimens, has not yet been afforded me. In the absence 

 of such materials I may cite the opinion of Dr. Torrey, who, as 

 Mr. Boott informs me, considers the American plant distinct as 

 a species : it is described by Beck under the name of Asple- 

 nium montanum (453), and by Michaux under that of Asple- 

 nium Adiantum-nigrum, (ii. 265). 



In Grreat Britain, the black spleenwort is universally distri- 

 buted, but in some districts far more abundantly than in others : 

 it occurs on rocks as a native habitat, but seems gladly to avail 

 itself of walls, old buildings, ruins and hedge-rows ; on ruins it 

 is often very ornamental. 



The radicles are very black and wiry : the caudex tufted, 

 black, and covered with setiform scales : the stipes is extremely 

 smooth, shining, and generally of a black or dark purple colour, 

 at its base are a few scattered pointed scales. The fronds sel- 

 dom appear before the end of May or the beginning of June ; 

 at first their position is nearly erect, but they soon begin to 

 droop, and finally become quite pendulous ; they arrive at ma- 

 turity in October, and continue perfectly green and vigorous 

 throughout the winter, until the ensuing May, or even June : 

 they are nearly always fertile. The form of the frond is trian- 

 gular, its apex being acute and attenuated : it is pinnate : the 

 pinnae are triangular, acutely pointed, pinnate, and alternate : 

 the pinnules again are alternate and triangular, and the lower 



