62 THE BRITISH FERNS. 
species, and some modern botanists continue to do the same; but 
the plant is too nearly akin to Asplenium lanceolatum to be sepa- 
rated from it, and the general structure of its sori is asplenioid 
not athyrioid. There is occasionally manifested a slight tendency 
to produce the arcuate sori characteristic of Athyrium, but this is 
very rare, and does not occur in a sufficient degree to necessitate the 
removal of the species from the neighbourhoood of Asplenium lan- 
ceolatum, with which in all other respects it so exactly accords. 
This rupestral and mural species is one of our rarest native Ferns, 
and is, indeed, considered by many botanists as altogether an alien. 
It is true that it has latterly been found only in situations which 
seem to support this opinion, but there are also positive state- 
ments of its having been found im a wild state, that we cannot 
reject. Moreover, while many probable situations for it remain 
unsearched by a scrutinising eye, we are unwarranted in concluding 
that it does not now exist in a wild state; and even if the search 
had been much more complete, the positive evidence which exists 
as to its former occurrence cannot be set aside. We are, therefore, 
as it seems to us, bound to retain it in the British Flora. Hudson 
first records our plant as a native, giving as habitats: Hammer- 
sham Church, and Wybourn, Westmoreland, from the former of 
which, according to. Sir J. E. Smith, it was brought alive to Kew 
by the late Mr. Aiton. In Lightfoot’s Herbarium, as we learn from 
Sir W. J. Hooker's account,* on the opposite folio to that on 
which are fastened specimens of this species, is written by Light- 
foot himself: “This I gathered on Amersham Church, Bucks.” 
Bolton certainly figures this very plant (the plate is dated 1785), 
and he writes thus of it: “Fountain Polipody is said to grow on old 
walls and rocks, above Hammersham Church; in stony places near 
Waybourn, in Westmoreland. The specimen here figured and 
described was sent to my brother, A.D. 1775, by a gentleman who 
gathered it in Buckinghamshire, and mistook it for the Acrostichum 
ilvense.” Sir W. J. Hooker justly remarks, one does not see well 
how the accuracy of such statements, Lightfoot’s personal one espe- 
cially, can be called in question. Several more recent instances of 
* Hooker, Kew Journal of Botany, vii. 341. 

