
GENERA AND SPECIES. 37 
PLATE V. 
POLYPODIUM INCANUM. Swartz. 
THE SCALY POLyYpopy. 
This fern is essentially tropical in its distribution, growing 
in great abundance throughout the Southern States, but 
rarely extends so far north as Kentucky, and is occasion- 
ally found in Indiana and Illinois. It usually grows upon 
trees, but sometimes on overhanging rocks. Southward it 
.is luxuriant on live-oaks, and, in this latitude, is found 
oftenest on the oak and sycamore. The illustration is from 
a specimen found near Rock Springs, Oldham County, 
growing upon a sycamore tree, extending along the trunk 
for the space of thirty feet, commencing about ten feet 
from the base. It grew mainly on the southwest side of 
the tree, and appeared to have a good foothold, having 
apparently existed there for years. The roots, of course, 
are in no way connected with the tree, as is the case with 
the mistletoe, being merely imbedded in the moss and 
earthy matter deposited upon the bark. It has been ob- 
tained at the mouth of Elk Lick, Kentucky River (Short) ; 
near Lebanon, Marion County (Knott); at Livingston, 
Rockcastle County; on Rough Creek, Grayson County ; 
near Rockcastle Springs, Laurel County (Miss Rule); at 
Rock Springs, Oldham County; near Cumberland Gap, 
Bell County (Jordan); and in Hardin and Edmonson coun- 
ties, in Kentucky, and upon oak-trees and cliffs near the 
Ohio River, in Perry County, Indiana (Smith). 
Prof. Hussey says: “I found this fern in a very dry situ- 
ation on the upper surface of the low cliff which borders the 
depression in which the mouth of Mammoth Cave opens. 
Standing with the back to the cave, near its mouth, the rock 
