460 FILICES. 



pinnatifid, except at their base, where the bottom pair of segments are often so 

 deeply separated as to form two little pinnules. Rounded- leaved Woodsia. 



3. W. obtusa Torr. : stipe and rachis somewhat chaffy ; frond lanceolate, 

 somewhat bipinnate, minutely glandular-pilose ; divisions pinnate or deeply 

 pinnatifid ; segments oblong, obtuse, crenate-toothed ; sori mostly solitary 

 on each lobule of the segments, and near the sinus. ( Torr. N. Y. Fl.} 

 W. Perriniana Hook. <$ Grev. Alsophila Perriniana Spreng. Aspidium 

 obtusum Willd. 



Rocky banks. Can. to Car. ; rather rare. July. 2J.. Fern 8 12 inches 

 high. Stipe 2 3 inches long, straw-colored, chaffy. Frond covered with 

 a minute glandular pubescence ; the divisions ovate-oblong. Sori small, at 

 length almost confluent. Indusium hemispheric, at length opening at the top 

 with an irregular lobed margin. Dr. Torrey states that the Alsojihila Perrini- 

 ana was described by Sprengel from specimens sent by him, which were placed 

 by mistake in a collection of plants brought from the West Indies by M. Perrin. 



Obtuse Woodsia. 



5. CISTOPTERIS. Bernh. Bladder Fern. 

 (From the Greek Kiffrtj, a box, and nrtpis, a fern..} 

 Sori roundish. Indusium inserted by its broad cucullate 

 base at the under side of the sorus, opening by its lengthened 

 free extremity which points towards the apex of the segment. 



1. C. fragiiis Bernh. frond bipinnate ; pinnae ovate-lanceolate ; pinnules 

 ovate-lanceolate, deeply pinnatifid ; segments toothed ; rachis winged. 

 Aspidium fragile Swartz. A. tenuc Willd. Nephrodium ienue Mich. 



Moist rocks. Arct. Amer. to Ver. Mass, and N. Y. June, July. 1\. Fern 

 6 14 inches high, growing in tufts. Stipe slender, dark colored and a little 

 chaffy at base. Frond delicate, deep green ; pinnules somewhat variable in 

 their shape and divisions. Sori large, pale, mostly solitary, near the margins of 

 the segments. Indusium forming a sort of cup or hood. Brittle Bladder-fern. 



'2. C. bulbifera Bernh. : frond bipinnate, lanceolate, attenuate at the 

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

 natifid ; rachis bearing bulbs ; sori minute. Aspidium buttnferum Swartz. 

 Nep/irodium bulbiferum Mich. 



Shady rocks. Can. to Penn. and Ohio ; common. July. 7J.. Fern some- 

 times 2 feet or more high, growing in tufts. Stipe smooth, pale. Frond nar- 

 row, smooth, green, much elongated and often bending over at the end. Rachis 

 bearing greenish somewhat flattened bulbs, which are about the size of a pea. 



Bulb-bearing Bladder-fern. 



6. ASPLENIUM. Linn. Spleenwort. 



(From the Greek a, privative, and <nrA^, the spleen ; from its supposed medici- 

 nal virtues.) 



Sori oblong or linear, oblique, scattered. Indusium of the 

 same shape, superficial, arising from the lateral veins, and open- 

 ing longitudinally on the side towards the midrib. 



* ^Frond pinnate. 

 I. A. angustifolium Mich. : frond pinnate; pinnae linear-lanceolate, ere- 



