134 ENGLISH BOTANY. 



out, the frond more tapering, the pinnae persistent, the lower ones 

 with longer stalks, more evidently three-lobed, and as large as or 

 larger than the succeeding pair, the middle ones smaller and not 

 pinnately-lobed ; it also is not densely glandulose on the rachis, 

 lamina, and indusium, and the latter is not entire but jagged at the 

 edges, as in A. Petrarchan, and the sori are longer and narrower. 



From A. Ruta-muraria it differs in the frond being linear, only 

 once pinnate, and in the pinnse having much shorter stalks, with a 

 more decided mid-vein, and the sori on the middle pinnas diverge more 

 from the median line of the pinnae. The stipes, rachis, venation, sori, 

 and indusia are, however, more like those of A . Ruta-muraria than of 

 any other British Asplenium. 



A. Clermontae belongs to a group of forms intermediate between A. 

 Trichomanes and other species of this genus, and which are generally 

 believed to be hybrids. These have been found in very small quantity, 

 often only single roots, where A. Trichomanes grows in company with 

 those species between which and A. Trichomanes the forms to which 

 I allude are intermediate. These are in the first place A. adulter- 

 inuin, Milde, which has been found in Northern Bohemia and near 

 Schonberg in Moravia ; this is intermediate between A. Trichomanes 

 and A. viride, and Milde considers it as certainly a hybrid. 



The next is A. dolosum, Milde, of which a single caudex was found 

 by Milde growing with A. Trichomanes and A. Adiantum-nigrum at 

 Meran in the Southern Tyrol, and which he also believes to be a 

 hybrid ; I have not seen this form, but it evidently approaches 

 A. Clermontae very closely : it differs by having the stipes entirely 

 and the rachis partly blackish, the pinnae more deeply divided and 

 with acute teeth, and the indusium quite entire. 



The third form is A. Heufleri, Beichardt, which was found growing 

 with A. Trichomanes and A. Germanicum between Yilpian and 

 Molten, in the Southern Tyrol, and at Eichorn, Moravia : this is quite 

 intermediate between the two species with which it grows, and is 

 considered by Milde to be a hybrid. 



I have scarcely any doubt that A. Clermontae is a hybrid between 

 A. Trichomanes and A. Ruta-muraria, between which it is quite inter- 

 mediate, and it ought to be looked for in other places where these t\\ o 

 species grow together. The plant has been eradicated at Ravensdale 

 Park, but it is quite possible it may survive in some fern-grower's 

 collection. I have followed the example of Milde in giving a distinct 

 name to this form. 



It is but an inference that ferns do produce hybrids, as it has never 

 been actually proved by experiment, but every new intermediate form 

 which exists in extremely small quantity and is found in circumstances 

 where the supposed parents grow together adds to the probability of 

 hybridization in ferns. A. Clermontaa has a peculiar interest, as so 

 many of the supposed hybrids cluster round A. Trichomanes. 



Lady Clermont's Spleenwort. 



