FILICES. 113 



natifid, the lower slightly more distant ; sori medium size, 

 nearly marginal ; indusia more or less toothed at the margin. 

 {Polypodium montanum Vogl., P. oreopteris Ehrh.) British 

 Columbia (Macoun), Unalaska (Turner). 



9. D. Nevadense (Eat.) Unde. Rootstock creeping, 

 densely covered wiili the persistent bases of former stalks; 

 stipes short, scaly below ; fronds 1^°— 3° long, lanceolate, with 

 pinnae linear-lanceolate from a broad base, and crowJed seg- 

 ments slightly hairy on the veins and with minute resinous 

 particles ; sori small, nearer the margin than tlie vein ; indusium 

 minute, furnished with a few dark-colored marginal glands and 

 with jointed hairs on the upper surface. California. 



\X Rootstocks stout, erect, forming a short caudex ; fronds in a 

 crown. 



10. 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 

 1° — 4" long, lanceolate, caudate-acuminate, much narrowed at 

 the base; pinnse 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. 



\\\ Rootstocks slender, creeping ; fronds scattered. 



11. D. Noveboracense (L.) Gray. Rootstocks wide creep- 

 ing; fronds 1° — 2° long, 4'— 6' broad, tapering both ways from 

 the middle; pinnse 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- 

 podiutn Noveboracense L., Aspidiuni t/ielvpter aides Swz.) North 

 Carolina to Arkansas and northward. 



ft Lower pinficc little smaller than those above. 

 \ Veins forked. 



12. D. thelypteris (L.) Gray. Rootstock creeping; fronds 

 lanceolate, scarcely narrov/er at the base, 1° — 2° long, 4'— 6' 

 wide, membranous; pinnse lanceolate, with obtuse segments 

 which often appear acute from the strongly revolute margin; 

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



