


218 BRITISH FERNS 
gether with intermediate types, which have raised in some 
minds a little doubt as to their absolute distinctness. Р. 
aculeatum, however, frequents mountain glens to a great elevation, 
so that the possibility of wind-borne spores must be admitted. 
The Holly Fern, too, is open to variation, and, obviously, if it 
“ sported,” as both its relatives do, in the direction of increased 
subdivision, its main difference from P. aculeatum would disappear. 
A bipinnate “ sport ”of P. lonchitis would infallibly be ranked as 
P. aculeatum unless its pedigree could be certainly determined. 
The writer, indeed, found on Ben Lawers, near the top, amongst а 
numerous group of the Holly Fern, an apparent plant of P. aculea- 
tum, which, however, failed to survive removal, though that species 
is usually very easy to re-establish These points we merely 
record for the guidance of future students, who may observe similar 
cases and follow them up. P. lonchitis has not varied very much ; 
we can only mention two instances. 
CRISTATUM.— This is a very good crested variety, found on Ben 
Qui, in Scotland, by Dr. Craig, and we believe by others elsewhere. 



P. lonchitzs imóricatum. 

Fig. 254. 
IMBRICATUM (Fig. 254).—An imbricate, dense form recorded as 
the Irish type of the species, but which we have found on Ben 
Lawers, in Scotland ; Mr. Boyd has also found it in both countries. 
PSEUDATHYRIUM ALPESTRE (THE MOUNTAIN LADY 
FERN) 
(Plate XXXIII) 
This Fern with numerous botanists ranks as a member of the 
Polypodium family on account of its dot-like fructification and the 
apparent absence of any cover. Хо one, however, who is acquainted 
with the Fern in its growing state can accept this classification, 
since it agrees in size, make, and general character so closely with 
Athyrium filix-femina, the Lady Fern, as to compel the belief 
that it is really a mountain form, if not of that identical species, 
at any rate of the same genus. It is only found at high levels on 
our Scottish mountains, above the levels at which the Lady Fern 












