HOLLY FERN. 
167 
strong, black and wiry ; 
nus Aspidium to those tropical species placed by the author as 
its types, and the genus Polysticlium to the leading species Lo7i~ 
chitis, and those cognate ferns distinguished by a similar peltate 
involucre. 
The roots of this species are long 
the rhizoma is tufted and scaly : 
the fronds appear early in the 
spring, arrive at perfection in Sep- 
tember and October, and remain in 
full vigour until the following sum- 
mer j the form of the frond is linear- 
lanceolate and pinnate. In the 
Twll du plant, which I have figured 
on the opposite page, the habit is 
lax and drooping. The pinnae are 
crowded, and extend nearly to the 
base of the stem, which is covered 
with chaffy scales ; they are some- 
what crescent-shaped, auricled on 
the upper side next the stem, ser- 
rated and acutely spined ; each 
pinna is twisted, a character least 
apparent in the Welch, and most 
so in the Irish specimens, in which 
the auricled portion of each pinna 
passes behind the pinna immedi- 
ately above it, and projects behind 
the fronds almost at right angles 
with the stem : the Scotch speci- 
mens are intermediate in this res- 
pect. In the Welch and English 
plants the colour of the frond is 
dull green,, much resembling that 
of P. aculeatum, while in the Irish, 
and some of the Scotch specimens, the upper surface is of a 
full, rich, shining green, the substance thick and leathery, and the 
whole frond as rigid and prickly as a spike of little holly leaves, 
so much so indeed that the fronds are not to be flattened for 
