14 FLOSA OF FHILADELPHIA. 



2, FlLix FRAGlLis (L.) UndcTW. M. p. 17. Shaded cliffs and rocky woods. 

 Summer. 

 General, but not in southern New Jersey except Burlington — Medford 

 (Br.). 



13. WOODSIA E. Br. 



Indusium minute or evanescent, flat, concealed beneath the sorus, its margin 

 cleft into slender hair-like segments. 1. TV. Ilve7isis. 



Indusium distinct, at first enclosing the sporanges, splitting into jagged 

 lobes. 2. W. obtusa. 



1. WooDSiA Ilvensis (L.) E. Br. M. p. 18. Exposed rocks. Summer. 



Buds— Noekamixon. C/iesier— Black Eock (Fl. C). Lehigh— l^era's 

 Mill, near Whitehall (Kr.). 



2. WoODSiA OBTUSA (Spreng.) Torr. M. p. 18. Eocks. Summer. 



14. DENNSTAEDTIA Bernh. 



1, DENNSTAEDTIA PUNCTiLOBULA (Michx.) Moore. M. p. 19. Open places. 

 Summer. 



15. MATTEUCCIA Todaro. 



1. Matteuccia Stbuthiopteris (L.) Todaro. Ostrich Fern. M. p. 19. 

 Alluvial soil. Summer. 

 Philadelphia — Upper Wissahickon (Ee.). Bucks — Nockamixon. Lan- 

 caster—York Furnace (Br.). Lehigh— Coplay (Kr.). Northampton— 

 (P.). Dauphin— (P.). 



Burlington— Crosswick's Creek (C). Eunterdon—Bosemont, Bull's 

 Island, Frenchtowm, Lambertville (C). 



16. ONOCLEA L. 

 1. Onoclea sensibilis L. Sensitive Fern. M. p. 19. Moist soil. Summer, 



Order 2. SALVINIALES. 



Family 1. MARSILIACEAE R. Br. 



1. MAESILIA L. 



1. Marsilia quadrifolia L. M. p. 20. In water. Summer. 

 Delatvare—Crum Lynn (Le.). 



Orders. EQUISETALES. 

 Family 1. EQUISETACEAE Michx. Horsetail Family. 



1. EQUISETUM L. Horsetail. 



Stems annual ; stomata scattered. 



Stems of two kinds, the fertile appearing in early spring before the 

 sterile. 

 Fertile stems simple, soon withering; sheaths of branches of sterile 



stems 4-toothed. 1. F. arvense. 



Fertile stems branched when old, only the apex withering. 



2. E. sylvaticum. 



