44 American Midland Naturalist Monograph No. 7 



13. Leaves pedate, the stipe forked at the summit, dark brown or 

 black, smooth, glossy; pinnules flabellate; sori several, distinct 



15. Adianturn 



13. Leaves not pedate, the stipe simple; sori apparently continuous 

 along the margin of the pinnules. 

 14. Sori borne near the tips of separate veins; rhizomes scaly; 

 chiefly small, rupestral ferns. 

 .15. Leaves delicate, strongly dimorphic; stipe straw-colored or 



pale brown 13. Crypto gramma 



15. Leaves firm, nearly or quite uniform; stipes dark brown or 

 blackish. 



16. Leaf-blades glabrous 14. Pellaea 



16. Leaf-blades pubescent 16. Cheilanthes 



14. Sori borne on a heavy marginal vein extending around the 

 lobes; leaves coarse, ternate; rhizomes horizontal, black, not 

 scaly 17. Pteridium. 



1. Onoclea L. — Sensitive Fern 

 O. sensibilis L. Moist woods, or edges of meadows, common. 



2. Matteuccia Todaro — Ostrich Fern 



M. struthiopteris (L.) Todaro. Wet ground, not common; n. 111., 

 southward to Peoria Co. [Pteretis struthiopteris (L.) Nieuwl.]. 



3. Cystopteris Bernh. 



1. Leaves broadly lanceolate, acute, 20-40 cm long, the basal pair of 

 pinnae usually slightly shorter; bulblets none; moist soil in 

 woods, common; the most abundant fern in 111. Brittle Fern 

 C. fragilis (L.) Bernh. 



1. Leaves narrowly lanceolate, 30-120 cm long when mature; axils 

 of some of the upper pinnae usually bearing small bulblets on 

 the lower surface; basal pair of pinnae the largest; on moist 



cliffs in shaded ravines, not uncommon. Bulblet Fern 



C. bulbifira (L.) Bernh. 



4. Woodsia R.Br. 



1. Leaves 20-50 cm long, minutely glandular; petiole not jointed; 

 indusium ample, with few broad spreading jagged lobes; cliffs, 

 not common. Clift' Fern W. obtusa (Spreng.) Torr. 



1. Leaves 5-15 cm long, rusty-chaffy beneath; petiole jointed a short 

 distance above its base; indusium inconspicuous, the divisions 



filiform; cliffs, rare; Ogle Co. Rock Woodsia 



!: W. ilvensis (L.) R.Br. 



5. Dennstaedtia Bernh. 

 D. puncfilobula (Michx.) Moore. Hay-scented Fern. Sandstone 

 cliffs in wooded ravines, rare; Wabash Co., Schneck; Lusk Creek, Pope 

 Co., Bailey & Swayne 2759. 



