198 
THE POLYPODIES. 
cristatum with pinnules variously forked and crested. 
:\ form from West Virginia has recently been described 
as P. vulgare deceptum. It differs from the common 
form in being somewhat larger with narrower, pointed 
pinne. This was earlier considered a mere form and 
named Jdiserratum. Considering the unimportant differ- 
cnees it displays, the earlier view seems the correct one. 
ure 
GRAY POLYPODY. 
Polypodium fucanum. 
In North America the polypody is 
found from Alabama to the far north 
and northwestward. Its natural habi- 
tat is upon rocks but it is occasionally 
found upon trees and logs where the 
atmosphere is moist. In the moister 
climate of England, it is said to be very 
commonly found on trees. In our 
western States, it is rare or absent, 
but its place is taken by several allied 
species that much resemble it. It isa 
tough and hardy species able to en- 
dure great extremes of temperature 
and is found in nearly all parts of the 
world. 
The Gray Polypody. 
The little gray polypody (Polypo- 
dium incanum) may be termed a strag- 
glerinto our territory from a warmer 
region. It is most abundant in the 
Tropics, where it grows on rocks, trees, 
walls and even on the roofs of the 
houses. In the northern part of its 
range, it is usually found on rocks or about the roots of 
