THE POLYPODIES. 199 



trees, although in the Gulf States it may be found high 

 upon the trunk or branches. 



In appearance it is nearly ' an exact duplicate of the 

 common species with the same creeping, scaly rootstock 

 and leathery, pinnatifid, or pinnate, fronds. It is, how- 

 ever, rather smaller and further distinguished by having 

 the stipe and under surface of the blade thickly covered 

 with gray, or brownish, peltate scales with darker centres. 

 The upper surface may be slightly scaly, though it is 

 usually smooth. The sori are of medium size and borne 

 near the margins of the pinnules but are seldom notice- 

 able owing to the scales by which they are surrounded. 

 Usually they are so deeply sunk in the blade as to form 

 little bosses on the upper surface. 



Since this species grows in situations where moisture 

 is a very uncertain quantity, it has acquired the trick of 

 curling up its fronds when drought comes and remaining 

 in a comatose condition until the next rain, when they are 

 again unrolled and life proceeds as before. During a 

 drouth the fronds have been known to uncurl in a heavy 

 dew. 



Among its common names are hoary polypody, scaly 

 polypody, tree fern and resurrection fern. Tree fern is 

 from its habit of growing in the treetops, and resurrection 

 fern refers to its habit of revival after a drought. 



This species is found as far north as Virginia, Illinois 

 and Missouri but is not common except in the Gulf 

 States. According to strict priority, this species should 

 have polypodioides for its specific name. This being 

 translated would mean, simply, a polypody that is like a 

 polypody ! Incanum is a name far better known to bot- 

 anists and is the one generally used. 



