196 



THE POLYPODIES. 



ultimately be included in this family notwithstanding 

 the absence of the indusium. For our present purpose 

 we shall include them with the other non-indusiate 

 forms. 



COMMON 

 POLYPODY. 

 Polypodium vulgare. 



The Common Polypody. 



Wherever there is a shaded ledge of 

 rocks in the northeastern States one is 

 almost sure to find the polypody (Poly- 

 podium vulgare]. There is no question 

 as to choice of location with this sturdy 

 species. All are alike to it, provided 

 there are rocks upon which it can grow. 

 The only preference it has is for the 

 tops and upper shelves of the rocks 

 where the soil is moderately dry. So 

 characteristic is it in such situations 

 that when one sees a fern clad rocky 

 summit from a distance too great to 

 discern the individual fronds he identi- 

 fies them with confidence as this spe- 

 cies. 



The fronds of the polypody are thick 

 and leathery and remain green all 

 winter. yThey grow from a slender, 

 brown-scaly, branching rootstock that 

 creeps at the surface of the soil, and 

 are produced during most of the early 

 summer. They are ordinarily about a 

 foot long with a short slender stipe and 

 narrow pinnatifid or pinnate blade. 

 The pinnules are linear, usually blunt at the ends, and 



