POLYPODIUM calcareum.
Rigid Three-branched Polypody.
CRYPTOGAMIA Filices.
Gen. Char. Fructifications scattered, in roundish doté,
not marginal. InvolUcrum none.
Spec. Char. Frond three-branched: branches bipin-
nate, erect, somewhat rigid, the lobes bluntish and
slightly notched. Dots o f seeds confluent.
Syn. Polypodium calcareum. Sm. FI. Brit. 1117.
P. Dryopteris. Dicks. Dr. PL 16. Bolt. Fil. 53. t. 1.
Dryopteris Tragi. Ger. em. 1135.
^ATH ERED on the 27 th of last June at Matlock bath,
DerbyShire. It grows copiously among grass and bushes on
the crumbling calcareous stone, or tufa, deposited, in the
lapse of ages, by the Matlock water, and in removing a large
bed of which, before Saxton’s Lodging-house, the skeleton
of a large animal of the Deer kind was lately found. See Pennant’s
Brit. Zool. ed. 4 . v. 1. 5 2 .
I never observed this species in any other place, nor was I
for some time convinced of its being distinct from P. Dryopteris
figured in our 9th vol. t. G\6 . I am still uncertain whether
the synonyms of any of the more accurate cryptogamists of
Germany belong to it.
The root is, of course, perennial, and creeps like that of
P. Dryopteris, but is thicker and commonly shorter. The
base of the stem is scaly, not smooth, and the whole frond
is firmer and more rigid, the three principal branches generally
smaller, nearly erect, and by no means flaccid or loosely
pendent. The young capsules are pale, without any involu-
crum; when ripe they become brown or black, and run
together, covering the whole back of the leaf, whereas those
o f P . Dryopteris remain in distinct dots.