POLYPODIACEAE 



51 



Leaves dimorphous; veins of sterile blade 

 freely anastomosing. 

 Sori oblique to the midribs or irregularly disposed. 

 Veins free; sori all oblique to the midribs, 

 single on the side of the veinlets next a 

 midvein, or crossing the veinlets and 

 recurved. 

 Sori with rare exceptions single. 

 Sori often single, often recurved. 

 Veins freely anastomosing; sori variously dis- 

 posed. 

 Sori borne at or very near the margin. 



Sporanges borne within a special cup-shaped indusium. 

 Sporanges not borne within a special cup-shaped in- 

 dusium; sori with indusia formed entirely or in 

 part by the revolute or reflexed more or less modi- 

 fied leaf-margins. 

 Sori distinct, borne on the under side of the reflexed 



lobes. 

 Sori wholly or partially confluent. 



Sori borne on a vein-like receptacle connecting 

 the ends of the free veinlets; indusium 

 double. 

 Sori borne at or near the ends of the free 

 veinlets; indusia single. 

 Leaves dimorphous. 

 Leaves uniform or nearly so. 



Sori confluent, forming a wide sub- 

 marginal band; segments smooth or 

 nearly so. 

 Sori distinct or contiguous; segments 

 usually pubescent, tomentose or 

 scaly. 



9. LORINSERIA. 



ii. asplenium. 

 12. Athyrium. 



10. Camptosorus. 



4. Dennstaedia. 



13. Adiantum. 



14. Pteridium. 



15. Cryptogramma. 



16. Pellaea. 



17. Cheilanthes. 



1. Onoclea L. 

 O. sensibilis L. In moist soil: Newf. to Sask., south to Okl. 

 and the Gulf States. 

 Common throughout the range except the pine-barrens. 



2. Matteuccia Todaro (Struthiopteris Willd.) 

 M. Struthiopteris (L.) Todaro. In moist thickets, especially 

 along streams: N. S. to Va., west to Br. Col. and Iowa. Also 

 in Eu. and Asia. 



Conn. Throughout the state but rare, more common in the 

 Connecticut River Valley and northward than elsewhere. 



N. Y. The region of the Caiskills, in Delaware and Greene 

 counties. 



N. J. Reported from but not recently collected in northern Bur- 



