500 



FILICES. 



WOODSIA. 



* Woodsia proper. Involucre minute, concave, covered by the capsules ; the margin fringed with long hairs. 



1. Woodsia Ilvensis, R. Br. Rusty Rock Polypody. 



Frond broadly lanceolate, pinnate ; the pinnae oblong, obtuse, broader at the base, deeply 

 pinnatifid, with oblong obscurely crenate segments ; the under surface, as well as the rachis 

 and stipe, clothed with rufous chaffy scales. — R. Br. 1. c. ; Pursh,fl. 2. p. 660 ; Bigel. fl. 

 Bost. p. 389 ; Torr. cornpend. p. 381 ; Beck, hot. p. 451 ; Darlingt. fl. Cest. p. 579 ; 

 Hook, in Engl. hot. suppl. t. 2616, and sp. Fil. p. 63. W. rufidula, Beck, I. c. Acrosti- 

 chum Ilvense, Linn. sp. 2. p. 1528. Polypodium Ilvense, Swartz. Nephrodium rufidalum, 

 Michx. fl. 2. p. 269. Aspidium rufidulum, Willd. sp. 5. p. 282 ; Pursh, I. c. 



Fronds 2-4 inches long and about an inch wide, growing in tufts, somewhat coriaceous, 

 slightly hairy above ; the under surface somewhat thickly clothed with rusty scales. Stipe 

 1-3 inches long. Sori small, distinct when young, but at length somewhat confluent, and 

 partly concealed by the chaffy scales, situated near the margin of the segments. Involucre 

 very small ; the margin cut into numerous capillary segments. Capsules slightly pedicellate. 



Crevices of rocks, particularly along the banks of rivers. Fr. June. This fern is a native 

 also of the northern part of Europe. 



** Hypopeltis, Torr. Involucre hemispherical or globose when young, open at the top, with an irregular lobed margin. 



2. Woodsia obtusa, Torr. Woodsia. 



Frond broadly lanceolate, somewhat bipinnate, minutely and glandularly pilose ; divisions 

 rather distant, pinnate or deeply pinnatifid ; the segments oblong, obtuse, crenate-dentate ; 

 sori mostly solitary on each lobule of the segments, and near the sinus ; stipe and rachis a 

 little chaffy. — Torr. cat. pi. in geol. report of New-York, 1840 ; Hook. sp. Fil. p. 62. 

 W. Perriniana, Hook. <§~. Grev. ic. Fil. I. t. 68 ; Beck, hot. p. 452 ; Darlingt. fl. Cest. p. 

 580. Aspidium obtusum, Willd. sp. 5. p. 254 ; Pursh, fl. 2. p. 662. Hypopeltis obtusa, 

 Torr. cornpend. p. 380. Physematium Perrinianum, Kunze. P. obtusum, Hook. fl. Bor.~ 

 Am. 2. p. 259. Alsophila Perriniana, Spreng. 



Fronds 6-12 inches high, sprinkled with a short glandular pubescence ; the divisions ovate- 

 oblong, about an inch in length : segments or pinnules 3-4 lines long. Stipe and rachis 

 somewhat chaffy. Sori small, distinct when young, finally approximated but not confluent. 

 Involucre at first almost enclosing the sori, roundish, at length spreading, larger than the sori. 



Rocky woods, banks of rivers : frequent. Fr. July. The Alsophila Perriniana of Spreng. 

 is certainly our Woodsia obtusa. It was described by Sprengel from specimens which I 

 sent to him many years ago, placed by mistake in a collection of plants brought from the 

 West Indies by M. Perrin. 



