Proccediiv^s of the Ohio State Academy of Science. 285 

 13. Dryopteris. Adans. Shield-fern. 



Ferns with 2-3-pinnate or pinnatifid leaves and round sori 

 with cordate-reniform indusia. Veins free ; petioles not jointed. 



(.■Is fid in III ). 



1. Vascular bundles of petiole 2, free or united; veins simple or once 

 forked ; leaves thin-membranous. 2. 



1. Vascular bundles •"> or more; veins forking freely; te.xture of the leaf 



firmer. -■). 



2. Lower pinnae very much reduced; vascular bundles usually 



bridged D. noveboracensis. 



2. Lower pinnae little smaller than tlie middle ones; veins once forked; 



vascular bundles 2, distinct D. thelypteris. 



3. Leaves 2-pinnatifid or 2-pinnate, the segments not spinnulose 4. 



3. Leaves 2-pinnate or 3-pinnatifid, the segments spinulose-toothed. 6. 



4. Sori marginal; petiole densely scaly below; indusia con- 



vex D. inarginalis. 



4. Sori not marginal; petiole with few scales; indusia flat and 



thinnish. 5. 



5. Vascular bundles in petiole 5; pinnae widest at the base. 



D. cristata. 



0. Vascular bundles in petiole 7: pinnat widest at the middle. 



D. goldieana. 



f). Leaves ovate-lanceolate, usually not narrowed below.... Z). spinulosa. 

 (). Leaves elongated-lanceolate, usually narrowed at the base..!), boottii. 



1. Dryopteris noveboracensis ( L. ) Gr. New York Shield-fern. 



Rhizome slender and creeping ; leaves lanceolate, tapering 

 both ways from the middle, 1-2 feet long or more, petioles more 

 or less chalTy. On the ground in moist woods. General. 



■2. Dryopteris tJieiy' pteris (L.) Gr. Marsh Shield-fern. 



Rhizome slender and creeping; leaves lanceolate or oblong- 

 ianceolate, scarcely narrower at the base than at the middle, 

 usually two to four feet long. In swamps and marshes. General. 



3. Dryopteris cristata (T..) Gr. Crested Shield-fern. 



Rhizome stotit and densely chaffy; leaves evergreen, linear- 

 cblotig or lanceolate, acuminate, gradually and slighth' narrowed 



