POL Y PODIA CEsE. 1 1 1 



\ I Root stocks stout, erect, forming a short caudex ; fronds in 

 a crown. 



3. D. contermina (Desv.) Ktze., var. strigosa (Fee) 

 Unde. Rootstock often extending a foot above the ground; 

 stipes very stout, narrowly wing-margined near the base ; fronds 

 i" 4 long, lanceolate, caudate-acuminate, much narrowed at 

 the base; pinnae sessile, narrowly lanceolate from a broader 

 base, deeply pinnatifid, the under surface dotted with resinous 

 globules; veins simple; sori near the margin with minute 

 glandular somewhat pilose indusia. Fort Meade, Florida. 



JJf Rootstocks slender, creeping ; fronds scattered. 



4. D. Noveboracensis (L.) Gray. Rootstocks wide creep- 

 ing; fronds i 2 long, 4' 6' broad, tapering both ways from 

 the middle ; pinnae lanceolate, sessile, ciliate, and finely pubes- 

 cent beneath ; veins simple or those of the basal lobes forked ; 

 sori near the margin ; indusium minute, gland-bearing. {Poly- 

 podium Noveboracense L., Aspidium thelypter aides Swz.) North 

 Carolina to Arkansas and northward. 



ft Lower pinnce little smaller than those above. 

 \ Veins forked. 



5. D. thelypteris (L-) Gray. Rootstock creeping ; fronds 

 lanceolate, scarcely narrower at the base, i 2 long, 4' 6' 

 wide, membranous ; pinnae lanceolate, with obtuse segments 

 which often appear acute from the strongly revolute margin ; 

 veins regularly once or twice forked; sori crowded, 10 12 to 

 each segment ; indusium slightly glandular or glabrous. {Poly- 

 podium thelypteris L.) New Brunswick to Manitoba south to 

 Texas and Florida. 



\\ Veins simple. 



6. D simulata. Dav. Rootstock slender, brownish ; fronds 

 8' 20' long, 2' 7' wide, oblong-lanceolate, tapering to an 

 acuminate apex ; pinnae 12 20 pairs, lanceolate, the segments 

 obtuse, entire, slightly revolute in the fertile frond, finely 

 pubescent, especially near the midribs; sori rather large, some- 

 what distant, 4 10 to each segment; indusia finely glandular 

 at the margins. New Hampshire, Massachusetts. 



