Polypody 5 1 



of primary branches of midveins of leaf's segments and apex, 

 commonly covering, sometimes below, apex of veinlet, often 

 becoming confluent. 



Spores rather large, yellowish, oblong-reniform, minutely 

 areolated or reticulated, a single vitta or band along the con- 

 cave side. 



Habitat. Flat or slightly sloping surfaces of rocks, wood- 

 land banks, stone walls, etc. 



Range. Labrador and Newfoundland to Georgia, Alabama, 

 Missouri, Manitoba, and Keewatin. Probably has a wider 

 range toward the northwest. 



Poly podium vulgar -e. Linnaeus, Species Plantarurr, 1085. 1753. 



THE young leaves of Polypodium vulgare described here have 

 been mostly taken from offshoots of rootstocks of the older 

 plants: young plants attached to prothalli have not been seen. 



The forms of the leaf-blade at different stages of development 

 may be seen from Plates V, VI, and VII. 



Small notches, often obscure, occur between the primary 

 branches of the leaf's midveins and often between the veinlets 

 as well. By a deepening of the notches between the primary 

 branches of the primary midvein, the leaf's primary and, nor- 

 mally, only segments are formed. Almost, if not quite, coinci- 

 dently with this deepening, the section of leaf that goes to form 

 the segment lengthens at right angles or obliquely to the primary 

 midvein. The segments begin to form at the base of the leaf- 

 blade, and segment after segment are successively separated from 

 the part of the blade above, which continually lengthens at 

 apex. To a marked lengthening of the segments below the leaf's 

 apical section before the segments forming next above them have 



