12 FLOFiA OF PEILADELPEIA. 



hickon (Ee.) (Te.)j Shawniont (Sa.), Lafayette (Te.). Bucl's—Argua 

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

 land, Center Bridge (Ws.)- Moiitgomery—ljafajette (Wn.). Delaware 

 — Eockdale, Glen Mills, Eidley Greek, Whiskey Eun (Fu.), Swarthmore 

 (Pe.)j Columbine Eocks, Haverford, Mount Misery, Lenni (B. Sm.), Con- 

 cord (W. Tr.), Chad's Ford (Wn,). C^esier— Valley Forge (Ke.), near 

 Mortonville (St.). Lamcaster— York Furnace. Le/w^7i— Saegersville, P. 

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

 (B. C). 



Mercer — Princeton (Te.). Sunterdon — Eosemont, Lambertville, Mil- 

 ford (C). 



New Castle — Jessups, Mount Cuba, etc. 



9, POLYSTICHUM Eoth. 



1. PoLYSTiCHUM ACROSTiCHOiDES (Miolix.) Schott. Christmas Fern. M. p. 

 14. Eocky woods. Summer. 



10. DEYOPTEEIS Adans. Shield Fern. 



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

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



Lower pinnae little smaller than the middle ones. 



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



2. D. Thelypteris. 

 Veins simple; sori larger, distant 4-10 to a segment. 



3. D. simulata. 

 Texture firmer, sometimes subcoriaceous ; veins forking freely. 



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

 Indusia large, thinnish, flat. 



Pinna3 widest at base. 4. D. cristata. 



Pinnae 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. 7. Z>. spinulosa var. 



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

 of stipe pale brown. 8. D. Boottii. 



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. 15. Damp woods and shaded 



swamps. 

 Chester— Fsioli (Cr.). 



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



Summer. 



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

 Swampy woods. Summer. 

 Philadelphia — Wynnewood (Ee.). Delaware — Swarthmore (St.), near 

 Newtown Square (VP.). C/iester— Willistown Twp. (Pr.). Northampton 

 —Bangor (Pr.). 



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

 New Castle — Near Mount Cuba, Commons. 



