FILICES. 451 



12. A. Imlbiferum Wittd. : frond bipinnate, lanceolate, attenuate 

 above ; segments opposite, oblong, obtuse, serrate, the lower ones pin- 

 natifid ; rachis bearing bulbs ; sori minute. Nephrodium bulbi/erum 

 Mich. 



HAB. Wet rocks. Can. and N. S. ; common. July. ! 

 Fern 1218 inches high. Stipe smooth, pale. Frond narrow, 

 much attenuated at the summit, fine green and smooth. 



13. A. Jilix fotmina Willd. : frond bipinnate ; pinnules oblong- lan- 

 ceolate, incisely serrate ; serratures few-toothed, somewhat acute ; 

 ori oblong, straight. Asplenium JUiz-fcemina Spreng. 



HAB. Low shady grounds. Can. to Vir. Pursh. Bethlehem, 

 Penn. and N. W. Terr. Schtccinitz. July. If. Fern grow- 

 ing in tufts, 1 1-2 2 feet high. Frond with the general outline 

 oblong-lanceolate. Sori small, one on each segment of the pin- 

 nules, inserted laterally into its minute rnidrib, oblong and 

 straight, but at length by the pushing back of the involucre 

 becoming kidney shaped and appearing nearly round, but al- 

 ways, remaining distinct. 



x 14. A. asplenioides Willd. : frond bipinnate ; pinnules linear-lanceo- 

 late, incisely serrate ; serratures 2 3-toothed ; sori oblong, lunate, 

 at length confluent. Nephrodium asplenoidcs Mich. Asplenium athy- 

 rium Spreng. 



HAB. Shady woods. Throughout the U. S and Can. July. 

 21 Resembles the preceding, but has a broader outline, and 

 has the sori longer and lunate and parallel to each other, giving 

 it the appearance of an Asplenium. The involucre is larger and 

 remains firmly attached to the frond, &c. 



15. A. angvstum Willd. : frond bipinnate ; pinnules lanceolate, in- 

 cisely-serrate ; serratures sub-bidentate ; lower tooth longer ; sori ob- 

 long lunulate; stipe smooth. Nephrodium Jilix fotmina Mich. A$- 

 plenium michauzii Spreng. 



HAB. Shady woods. Can. to N. Car. July. If. Though al- 

 lied to the two preceding, this appears to be a good species. 

 The frond is smaller, being seldom more than a foot high ; it haa 

 . ' also a narrower outline. Dr. Hooker, however, considers it a 

 narrow-fronded variety of A.filizfamina. 



4. WOODSIA. Brown. 



Sori roundish, scattered, having beneath an involucre which 

 is cut at the edge into many capillary segments. 



1. W. ilvensis Eroicn: frond pinnate; pinnao lanceolate, deeply 

 pinnatifid, with numerous nearly uniform oblong segments. Polypo- 

 dium ilvense Willd. 



HAB. Rocky banks of streams. Can. and N. S. June. I(. 

 Fern 4 6 inches high, in dense tufts. Stipe brownish and scalj 

 below. Frond oblong or lanceolate ; pinna about 12, alternate. 

 This is not the W. ilvensis of Pursh. 



2. W. kyperborea Brown : frond pinnate ; pinna somewhat cordate, 



