Woodsia.] 
E ERNS. 
19 
4. — P0LYP0D1E M CALCAREUM. 
RIGID THREE-BRANCHED POLYPODY. LIME POLYPODY. 
(Plate 1, fig. 6. 
Cha. — Frond tri-pinnate, rigid. Branches upright. Lobes ob- 
tuse, deeply crenate. 
Syn. — Polypodium Calcarcum, Swz., Willd., Smith, Hook., Part., Gulp — 
Polypodium Dryopteris, Bolt., Dicks. Polypodium Dryopteris /3, 
With., 2nd edit. Polypodium Ilobcrtianum, Hoffm. — Neplirodium 
Dryopteris, Michx. 
Fig.—#. B., \b2b.—Bolt. 1. — Ger. 1135. 
Des. — This is so similar to the last, that when dried they are 
scarcely to be distinguished, hence the doubt of their claim as 
distinct species ; but when growing the eye will instantly see the 
difference between the two. The P. Calcareum is known from its 
root being thicker and less creeping, its frond rather large in size, 
much more rigid, quite upright, and of a dark green colour, its 
lobes more deeply cut, and stem more scaly towards the base, and 
on the upper part sprinkled over with fine white hairs ; its sori are 
browner and more numerous. 
I know not if the pubescence of the stem be a constant character ; if so, it 
alone is a sufficient diagnosis. My specimens are all hairy, and are the true 
plant received in 1835 from Mr. Wilson. 
Sit. — O n moist, shady rocks, &c. 
Hab. — Matlock Bath, Derbys., Dr. Howitt. Road-side under the Lover’s 
Leap, near Buxton, Derbys., Mr. H. C. Watson. Cheddar Cliffs, Somers., 
Mr. W. Christy. Arncliff and Gordale, Yorks., Mr. R. B. Bowman. Near 
Lancaster, Mr. Gibson. Sheddin Clough, 3 miles from Burnley, Lane., Mr. 
Leyland. Common about Settle, Yorks., Mr. J. Tatham. Not found in either 
Scotland or Ireland. 
Geo. — Recorded by Pursh and Michaux as occurring throughout North 
America from Canada to Pensylvania, and no doubt this is correct, as the 
description of Pursh so exactly accords with our plant ; though Swartz says 
that it is found in England only. 
WOODSIA, Br. PIAIR-FERN. 
(Named in honor of Mr. J. Woods, an eminent English Botanist.) 
Mr. Brown first separated from the Polypodium, Sec. this very distinct genus, 
which contains only two British and four foreign species, all very small plants, 
and natives of mountainous regions. The indusium is very singular and beauti- 
ful : it is attached under the mass of theca, enclosing them at first in a bag, it 
becomes. split into numerous segments, which look like hairs interspersed with the 
theca, and were so considered until Mr. Brown shoived their true nature in 
Trans. Linn. Soc. vol. 11. 
