128 HISTORY OP BRITISH FERNS. 



alternate venules, which are simple or forked, or sometimes 

 three-branched in different parts of the pinnule, the three- 

 branched ones, if present, occurring at the base, and the 

 unbranched ones at the apex. The sori are borne on that 

 branch which is towards the apex of the pinnule, and jointly 

 they form a line at a little distance from and on each side 

 of the mid vein. 



One variety of this Fern we have called Lastrea Filix-mas 

 incisa in the ( Hand-book of British Ferns/ and it has been 

 named Lastrea erosa, and I/. Filix-mas erosa, by others, in 

 the belief of its being identical with a plant called Aspidium 

 erosmn by an old author named Schkuhr which we think 

 it is not. However this may be, it is a magnificent variety, 

 much larger than the commoner form of the plant, attaining 

 four or five feet in height, and possessing the same general 

 features as that which has been already described, but 

 larger in every part, and having the pinnules more elongated 

 and tapering towards the point, more deeply cut along 

 the margin, the branches of the venules more numerous, 

 and the sori produced over a larger proportion of the sur- 

 face of the pinnule, in fact, usually almost reaching to its 

 apex. 



Another variety or starved form of this common plant 



