FiLicES. (ferns.) 593 



wi.h a double indusium. — Mountains of Alabama, and northward. — Fronds 

 2' -5' high, with a winged greenish rachis, and a stipe nearly as long as the 

 frond. 



7. A. Ruta-muraria, L. Fronds small, ovate, pinnate above, bipinnate 

 below, the divisions stalked, obovate-cuneate, toothed at the apex; veins forked 

 from the base ; fruit-dots few, indusia laciniate at the margin. — Rocks along 

 the mountains, and northward. — Fronds 2' -4' high. 



8. A. myriophyllura, Presl. Fronds delicately membranaceous, lan- 

 ceolate, narrowed below, 2 - 3-pinnate ; ultim.ate segments obovateK)blong, en- 

 tire or 2 - 3-lobed ; veins single in each segment or lobe, bearing below the 

 middle a solitary oblong fruit-dot. (A. Anchorita, Chapm. MS.) — On the walls 

 of a limestone cave at Schurlock's Spring, Jackson Co, Florida, Chapm. — 

 Fronds 3' -10' high, with short stipes and narrowly winged rachises. 



9. A. thelypteroides, Michx. Fronds ample, oblong-ovate, pinnate ; 

 the deeply pinnatitid pinna; lanceolate-acuminate from a broad sessile base ; the 

 lower ones smaller, distant, and deflexed ; the lobes oblong, obtuse, crenately 

 serrate; fruit-dots 8-12 to a lobe, at length confluent, those next the midrib 

 toward the ends of the pinna mostly double ; indusium convex, thickish. — 

 Rich woods in the upper part of Georgia, and northward. — Fronds l°-3° 

 liigh. 



§ 2. ATHYRIUM, Roth. — Indusium thin, atlnched to the upper side of the vein; 

 or rtcurvfd and crossincf the vein, attached to both sides of it, thus becoming reni- 

 form or shaped like a horseshoe. 



10. A. Filix-fCEmina, Bernh. Fronds ample, ovate-oblong ; pinna lan- 

 ceolate, numerous ; pinnules oblong or lanceolate, doubly serrate or variously 

 incised ; fruit-dots short, at length confluent. (Aspidium Filix-foemina, Swartz.) 

 — Low shady woods, Florida to Mississippi, and northward. — Fronds l®-3° 

 high. — A. asplenoides (Aspidium asplenoides, Swartz']) is said to differ in hav- 

 ing a creeping caudex. 



12. CYSTOPTERIS, Bernhardi. 



Fruit-dots 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-pinnatc fronds, and 

 short creeping rootstocks. 



1. C. fragilis, Bernh. Fronds ovate-oblong, l)ipinnatc ; the ovate-lance- 

 olate pinn;c mostly opposite, the lowest pair distant, smaller ; pinnules oblong 

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

 variously toothed or incised; indusium ovate, acuminate. (Aspidium tenue, 

 Swai-tz.) — Moist rocks on the mountains of North Carolina, and northward. — 

 Fronds 4' -8' long, on slender brownish stipes as long as the frond. Pinnules 

 varying greatly in shape and size. 

 50* 



