34 American Midland Naturalist Monograph No. 2 



2. BoTRYCHlUM Sw. — Grape Fern 



1. Sterile blade stalked, attached near the base of the plant; lateral veins of the 

 leaf-segments forked; epidermal cells with straight walls. 



2. Leaf-segments incised; woods, local B. dissectum Spreng. 



2. Leaf-segments merely crenate or serrulate. 



3. Blades thin; segments acutish; woods, rare, s. 111.; also Lee Co 



B. obliqimm Muhl. 



3. Blades thick, somewhat coriaceous; segments obtuse; woods, rare, n. 111. 



[5. ternatiim var. intermedium D. C. Eaton; B. silaijolium of auth., 

 not Presl} B. midtifidum (S. G. Gmel.) Rupr. 



\. Sterile blade nearly or quite sessile, attached near the middle of the plant, 

 thin, membranous, the segments acute, incised; lateral veins of the leaf- 

 segments unbranched; epidermal cells with flexuous walls; moist woods, 

 common B. yirginianiim (L.) Sw. 



6. Hymenophyllaceae Gaud. — Filmy Fern Family 



L Trichomanes L. — Filmy Fern 



T. boschianiim Sturm. On sandstone near a spring, Jackson Hollow, Pope 

 Co., Aug. 2, 1923, Mary M. Steagall 37 (Univ. 111. herb.). 



7. Osmundaceae R. Br. — Royal Fern Family 

 L OSMUNDA L. 



1 . Leaves 2-pinnate, some of them fertile at the apex and forming an erect 



terminal panicle; swampy ground or wet woods. Royal Fern 



O. regalis L. 



L Leaves 1 -pinnate. 

 2. Leaves of two kinds, the fertile and sterile ones separate; sterile leaves 

 1-pinnate, longer than the fertile; each pinna with a tuft of tomentum 

 at base; swampy ground n.e. 111. Cinnamon Fern O. citinamomea L. 



2. Leaves fertile at the tip, or wholly sterile, or some of the larger ones with 

 some of the middle pinnae fertile; pinnae lacking tufts of tomentum; 

 moist ground in woods. Interrupted Fern .O. claytomana L. 



8. Polypodiaceae R. Br. — Fern Family 



l.Sporani^ia enclosed in £;lobose or necklace-like brownish portions of the contracted and 

 modified fertile leaves; fertile and sterile leaves dissimilar. 



2. Sterile leaves 1 -pinnatifid, the veins reticulate; fertile leaves 2-pinnate; rhizome 

 horizontal, the leaves therefore solitary 1. Onoclea 



2. Sterile leaves 2-pinnatifid, the veins free; fertile leaves I -pinnate; rhizome short. 



erect, the leaves therefore tufted 2. Pierelis 



1. Sporangia on the margin or back of ordinary foliar or modified leaves. 



3. Indusium inferior or partly so (often evanescent). 



4. Sori marginal, in minute cup-like inferior indusia at the ends of the veins; leaves 



bipinnate, delicate, fragrant, sparsely glandular-pubescent beneath 



3. Dennstaedtia 



