AJIESIUM GERMANICUM. 261 



Newman, in his recent publication on ferns, has fallen into this 

 mistake, and conjoined the species, I think it not out of place 

 to communicate to the Botanical Society the following brief 

 observations. 



" The first character is taken from the form of the frond, 

 which is correctly stated by Sir Wm. Hooker to be bipinnate in 

 A. Ruta-muraria, and, in alternifolium, pinnate, the lower pinna 

 ternate ; the pinnae in both being alternate. Now, so far from 

 its being the tendency of attenuated or contracted forms of A. 

 Ruta-muraria to approach the pinnate form of alternifolium, 

 the truth of the matter is, that the more attenuated the former 

 is, the more distinctly bipinnate does it become ; or, in other 

 words, the nearer A. Ruta-muraria approaches alternifolium in 

 its general aspect and habit, the further and more visibly does 

 it diverge in tliis character. 



" The second character is taken from the indusium, with re- 

 gard to which it is hardly necessary to remark, that while that 

 of alternifolium has a smooth even edge, the edge in all varie- 

 ties of Ruta-muraria is invariably jagged or uneven, and this is 

 quite visible to the naked eye." — -Rev. T. Bell, in Trans. Bot. 

 Soc. Edinb. ii. 119. 



Without at all attemj)ting to undervalue these observations, 

 I would just observe that the peculiar form of frond had been 

 previously well described in the Floras of France and Germany, 

 and the supposed distinctive character of the involucre pointed 

 out by Sir "W. Hooker, who says, " Involucre entire " (Brit. 

 Flor. 442), and by Mr. Francis, who still more explicitly ob- 

 serves, " Indusium entire on the margin," (Analysis, 45). 



This fern appears to be nowhere common on the continent, 

 but it has been found here and there on rocks and walls in 

 Sweden, Hungary, Germany, France, and Italy. Beyond the 

 limits of Europe I am unable to trace its range. 



It is one of the rarest — perhaps the very rarest — of our Bri- 

 tish ferns. Although found in Scotland, England, and Wales, 

 six localities only are recorded — three Scotch, two English, and 

 one Welch. 



