154 
ASPIDIACEiE. 
I select the variety called dentata, as the most simple form, 
to begin the series. 
Cystea dentata, Smith. Polypodium dentatmn, Dickson. 
“ Rather smaller than Cystea fragilis, but 
agreeing with it in texture, colour, and ge- 
neral aspect. Root tufted, small. Frond 
for the most part correctly hipinnate, a few 
of the lower leaflets only, in luxuriant speci- 
mens, being pinnate or pinnatifid ; the leaf- 
lets are exactly ovate, or rounded, obtuse, 
pointless, copiously and bluntly serrated or 
toothed : their ribs wavy ; their base not 
decurrent, though seated on a winged mid- 
rib ; masses prominent, at length entirely 
confluent, of a uniform rich chestnut brown. 
I do not perceiv^e in the younger ones that 
peculiar blackness which is observable in 
P. fragilis. The cover is short, jagged, 
concave. I have never seen it in an early 
state before bursting.”^ Sir J. E. Smith 
has described this species, as far as regards 
the leading characters of the fronds, with 
great accuracy ; but he has made his spe- 
cies too lax by introducing into it a variety 
of specimens from Llangollen and Anglesea : 
these have nothing to do with Dickson’s 
original plant, which was found in Scotland, 
and is the only form of fragilis which I 
could find on the northern shoulders of Ben 
More, where it is most abundant, descend- 
ing even to the walls on the road-side between Killin and Tyn- 
drum. Sir J. E. Smith appears to have known nothing of the 
plant but from a dried frond : he makes no allusion to the re- 
flexed, drooping, and convex pinnae of the young fronds, or the 
more marginal arrangement of the clusters of capsules, characters 
which appear of some importance. 
^ Eng. Flor. iv. 287. 
