FILICKS. (FERNS.) 631 



15. CYSTOPTERIS, Bernhardi. 



Fruit-clots round, on the back of the free forking veins, covered when young 

 by a thin ovate or roundish hood-shaped indusium attached by the lower side 

 rather beneath the fruit-dot, its apex pointing toward the end of the vein, at 

 length reflexed or falling away. Delicate Ferns with 2 - 3-pinnate fronds, 

 and short creeping rootstocks. 



1. C. fragilis, Bernh. Fronds ovate-oblong, bipinnate ; the ovate-lance- 

 olate pinna? mostly opposite, the lowest pair distant, smaller ; pinnules oblong 

 or obovate, cuneate at the base and decurrent on the winged secondary rachis, 

 variously toothed or incised ; indusium ovate, acuminate. Moist rocks on 

 the mountains of Georgia, and northward. Fronds 4'- 8' long, on slender 

 brownish stipes as long as the frond. Pinnules varying greatly in shape 

 and size. 



2. C. bulbifera, Bernh. Fronds lanceolate, very long and attenuated 

 at the apex, often bearing bulblets beneath, bipinnate ; pinna? triangular-lance- 

 olate ; the lowest pair largest, distant ; pinnules oblong, crenately incised or 

 toothed, obtuse ; indusium roundish, truncate. Rocks on the mountains of 

 Georgia, and northward. Fronds l-3 long. The bulblets fall to the 

 ground, and form new plants, which are about two years in coming to 

 maturity. 



16. ASPIDIUM, Swartz. SHIELD FERN. 



Fruit-dots round, borne on the veins mostly below their apices. Indusium 

 round-reniform and fixed at the sinus, or orbicular and fixed by the depressed 

 centre. Veins with acute or attenuated apices. Our species have free veins 

 and 1 -3-pinnate fronds. 



1. LASTREA, Bory. Indusium round-kidney-shaped, fixed at the sinus. 



* Fronds thin and delicate, decaying in autumn: ultimate segments entire or 

 nearly so: veins simple or once forked. 



1. A. Thelypteris, Swartz. Fronds smooth, ovate-lanceolate, pinnate ; 

 pinna? lanceolate, often recurved, deeply pinnatifid ; the lowest 1-2 pairs 

 rather smaller ; segments oblong, obtuse, nearly entire, the fertile ones with a 

 strongly revolute margin ; veins mostly forked ; indusium minute, smooth. 

 Swamps and bogs, Florida, and northward. Fronds 10'- 18' long, with an 

 elongated stipe. This species and the next one have slender, nearly naked 

 rootstocks, which creep several inches in advance of the fronds. 



2. A. Noveboracense, Willd. Fronds lanceolate, tapering both ways 

 from the middle, pinnate ; pinna? lanceolate, hairy beneath along the midrib ; 

 the lowest 4-6 pairs gradually smaller, distant and defiexed; segments ob- 

 long, obtuse, nearly entire ; veins simple ; indusium minute, smooth. Low 

 grounds, North Carolina, and northward. Fronds l-2 long, on rather 

 short stipes. 



3. A. patens, Swartz. Fronds ovate or oblong-ovate, pubescent, espe- 

 cially on the veins beneath, pinnate ; pinnae lance-linear from a broad base, 

 deeply pinnatifid ; the lowest pair a little smaller and reflexed ; segments 

 oblong, often falcate, entire, or the upper basal one enlarged and pinnatifid ; 



