594 FILICES. (FERNS.) 



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

 the apex, often bearing bulblets beneath, bipinnate ; pinnte triangular-lanceolate ; 

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

 obtuse; indusium roundish, truncate. (Aspidium bulbiferum, Swartz.) Rocks 

 on the mountains of North Carolina, 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. 



13. ASPIDIUM, Swam. 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 ; 

 pinnae 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 1 0' - 1 8' 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. Noveboracen.se, Willd. Fronds lanceolate, tapering both ways 

 from the middle, pinnate ; pinnae lanceolate, hairy beneath along the midrib ; 

 the lowest 4-6 pairs gradually smaller, distant and deflexed ; segments oblong, 

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

 North Carolina, and northward. Fronds 1 - 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 ; 

 veins simple, free, or the basal ones meeting at the sinus between the segments ; 

 indusium small, pubescent. (A. molle, Kunze in Sill. Jour.) Low shady woods, 

 Florida to South Carolina, and westward. Fronds 1 - 3 high. 



* * Fronds thicker ; ultimate segments more or less serrate or toothed ; the lowest 



veins more than once forked. 



4. A. spinulosum, Swartz. Fronds ovate-oblong, thin, smooth ; bipin- 

 nate or below tripinnate ; pinnae oblong-lanceolate ; the lower ones broader, 

 triangular-ovate ; ultimate segments oblong, or linear-oblong, closely set on a 

 narrowly winged partial rachis, variously incised or serrate with spinulose teeth ; 

 fruit-dots small ; indusium deciduous, sparingly glandular at the margin. (A. 

 intermedium, Muhl.) Shady woods in the upper districts of North Carolina, 

 Tennessee, and northward. Fronds l-2 long, 5' -9' wide, varying greatly 

 in outline, and in the shape of the segments. 



