LASTREA. 
103 
cess of drying, before they yield up their vitality. These 
covers are at first little white scales. 
The veins of this species are also readily seen, and each 
pinnule will be found to have a flexuous midvein, with 
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 the 
branch towards the apex of the pinnule, and form a line of 
dots at a little distance on each side of the midvein. 
The variety of this Fern we have called incisa in our 
Handbook of British Ferns,"" has been named Lastrea 
erosa^ and L, Filix-mas erosa, by others, in the belief of 
its being identical with a plant called Aspidimn erosum 
by Schkuhr, — a belief to which we do not conform. It has 
also been called Lastrea affinis. It is a magnificent Fern, 
much larger than the commoner form of the plant, growing 
four or five feet or more in height, and having the same 
general features as those already described, only that it is 
larger in every part, and its pinnules are 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 surface 
