12 FLOBA OF PHILADELPHIA. 



hiekon (Ee.) (Te.), Shawmont (Sa.), Lafayette (Te.). Bucks— Argus 

 (Fr.) (Ja.), Zieglersville (Je.), Sumneytown (VP.);. Neshaminy, Rush- 

 "land, Center Bridge (Ws,). Montgomery— Lafayette (Wn.). Delaware 

 V-Rockdale, Glen Mills, Ridley Greek,. Whiskey Run (Fu.), Swarthmore 

 iPe.), Columbine Rocks, Haverford, Mount Misery, Leniii (B. Sm.), Con- 

 cord (W. Tr.), Chad's Ford (Wn.). Chester^ Valley Forge <Ke.), near 

 Mortonville (St.). Lancaster— York Furnace. , £eM#?i— Saegersville, P. 

 A. Lantz (B. C), Coplay (Kr.). Northampton— Above Easton, Porter 

 (B. C.).' 



Mercer— Princeton (Te.). Hunterdon — Rosemont, Lambertville, Mil- 

 ford (C). 



New Castle— Jessups, Mount Cuba, etc. 



9. POLYSTICHUM Roth. 



1. Polystichum acrostichoiDes (Miohx.) Schott. Christmas Fern. M. p. 

 14. Rocky woods. Summer. 



10. DRYOPTERIS Adans. Shield Fern. 



Texture thin-membranous; veins simple or once forked; leaves pinnatifid. 

 Lower pinnae very much reduced. 1. D. Noveboracensis. 



Lower. pinnae little, smaller than the middle, ones. 



Veins 1-2-forked; sori crowded, 10-12 tp a segment. 



2. D. Thelypteris. 

 Veins '■ simple ; sori larger, distant 4-10 to a segment! 



,, , . , 3. D. simulata* 



Texture firmer, sometimes subeoriaceous ; veins forking freely. 

 Leaves 2-pinnatifid or 2-pinnate; segments not spinulose. " 

 Indusia large, thinnish, flat. 



Pinnae widest at base. 4. ,D. cristata. 



Pinnee widest at middle. 5. D. Goldieana. 



Indusia convex, without marginal glands. ■■ 6. D. marginalis. 

 Leaves 2-pinnate or 3-pinnatifid; segments spinulose-toothed. 



Leaves ovate-lanceolate, usually not, narrowed below; scales of the 



stipe usually with dark centre. ' l.D. spinulosa var. 



Leaves elongated-lanceolate, usually narrowed at the base; scales 

 of stipe pale brown. 8. D. BoottH. 



1. Dryopteris Noveboracensis (L.) A. Gray. M. p. 14. Moist woods. 



Summer. 



2. Dryopteris Thelypteris (L.) A. Gray. M. p. 14. Marshes. Summer. 



3. Dryopteris simulata Davenp. M. p. 1$. Damp woods and shaded 



swamps. 

 Chester— Paoli 1 (Cr.). ; 



4. Dryopteris cristata (L.) A. Gray. M. p. 15. Swamps and wet woods. 



Summer. 



4a. Dryopteris cristata Gltntoniana (D. C. Eaton) Underw. M. p. 15. 

 Swampy woods. Summer. 

 Philadelphia— Wynnewopd (Re.). Dejawfire— Swarthmore (St.), near 

 Newtown Square (VP.) . Cheste r— Willistown Twp. (Pr.). Northampton 

 — Bangor (Pr.). n 



Camden— Little Timber Creek (C). Mercer— Trenton "(C). 

 New Castle — Near Mount Cuba, Commons. 



