OAK FERN , O R W o o d F e rn .
P o l y p o d iu m D r y o p t e r i s of Authors.
Polypodium pulchellum.-—Gray.
l o c a l i t i e s .
E ngla n d . . Northumberland,Cumberland, Westmoreland, Durham, Lancashire, sparingly; Yorkshire,
a t Arncliffe* and Richmond*; Cheshire; Shropshire, on the Titterstone
Clee Hill; Herefordshire, on the north side of Shobdon Wood Hill; Derbyshire,
a t Matlock*, Buxton*, Dovedale*, &c. in profusion , Wiltshire, at Box Quarries* ;
Somersetshire, Cheddar Cliff*; Devonshire; Monmouthshire, near T intein Abbey.
W al e s . . . Anglesea, near Beaumaris; Caernarvonshire, Bangor, Rhaiadr-y-Wenol, Pass of Lianberris,
Cwm Idwel, Snowdon, &c. &c.; Denbighshire, at Llangollen; Flintshire; Merionethshire,
near Plinlymmon; Radnorshire, a t Water-Break-its-Neck, and Craig-
Pwll-du; Brecknockshire, at Brecon; Cardiganshire, at the Devil’s Bridge and
Ponterwyd ; Glamorganshire, near Merthyr Tydfil.
Scotland . . Argyleshire, Perthshire, Dumfrieshire, Lanarkshire, in abundance; remarkably
luxuriant at Loch Katrine, near Tannuilt, near Callender, and at Corra Lynn.
I r e l a n d . . . County Antrim, a single plant on Knocklayd.
P o l y p o d iu m Dryopteris is one of our most elegant and
delicate ferns; it is almost entirely confined to wild and mountainous
districts, and shuns the vicinity of human abodes; it
prefers places overshaded by rocks or by thick foliage. The
roots are black and fibrous; the rhizoma black, wiry, and creeping;
in some situations, forming a dense mass like net-work.
The young fronds make their appearance in March and April,
each resembling three little balls on wires ; these gradually
unfold, and display the triple division. The fronds arrive at
* The plant called calcareum grows in these localities.
maturity early in summer, and disappear entirely before the
whiter ; they are fertile only.
In describing the form of frond, it must be premised that,
under the name Dryopteris, I am about to include the P. calcareum
of Sir J. E. Smith, and I do this because I know of no differences
by which I can distinguish them ; and in order to bring
the subject fairly before the reader, I shall quote verbatim Sir J.
E. Smith’s description, and give a figure of one of his specimens,
being one of the very fronds on which he founds the species.
P. calcareum, Smith. “ Frond three-
hranched : branches doubly pinnate,
erect, rather rigid : segments obtuse,
somewhat crenate. Masses of capsules
crowded, finally confinent.”—English
Flora, iv. 283. Sir J. E. Smith further
observes, that the rhizoma is
shorter and less extended than in
Dryopteris. “ The frond is also more
firm and rigid, its stalk more scaly
about the lower part. All the three
branches upright; smaller than Dryopteris,
rigid, and not loosely spreading ;
masses of capsules more crowded,
finally in some degree confluent, and of
a browner hue.”
Mr. C. C. Babington has pointed out
to me another character, which seems to
me of more value than either noticed by Smith. Mr. Babington
observes — “ P. calcareum may always he distinguished from
P. Dryopteris by being covered with minute stalked glands,
forming to the naked eye a mealy coat over the whole plant.
This is never, as far as my observation goes, to he found in
Dryopteris.” Still, with regard to this character, I am compelled
to add, that I can detect it in scarcely a tenth of the
fronds which have been shown me as those of P. calcareum. A
very obvious character, and one by which the varieties may be
more positively and definitely settled, is to he found in the
second pair of pinnæ. In Smith’s Dryopteris, these second
pinnæ have each a pair of sessile pinnulæ at their union with
the rachis ; and in the same author’s P. calcareum these sessile
pinnulæ are entirely wanting.