- 5 8- 



however, may be distinguished from other ferns by the form and 

 arrangement of the fruit-dots. Our species may be separated from 

 Eastern American ferns by the following key : 

 Fruit-dots round, without indusium, on the backs of ordinary 

 fronds. 



Fronds simply pinnate or nearly so. 



smooth, P. vulgare. 



scaly, P. incanum. 



The word polypody is said to be derived from the Greek and 

 to signify many feet in allusion to the branching rootstock of some 

 species. A less fanciful derivation, and probably the correct one, 

 would make it derived from the creeping rootstock of many of the 

 species, in which the numerous rootlets may be taken for feet. 

 There are nearly 400 species in the genus. In our illustration 

 figure 1 represents the tip of a frond of P. vulgare ; 2, a sorus en- 

 larged, and 3, a single spore-case still more highly magnified; 5 

 is a young fern " crozier," as the buds of ferns are called, showing 

 that the young fern leaves are coiled instead of folded, as other 

 leaves are; 4 is a pinnule of another fern showing the forking 

 veins possessed by ferns. 



NOTES ON AMERICAN FERNS-II* 



By William R. Maxon. 



^OLYPO D1UM vulgare acutum Moore? On August 24th 



last, the writer, in company with Mr. Charles L. Pollard, 

 collected (No. 25) on the mountain side at Quinnimont, W. 

 Va., several plants of a form of Poly podium vulgare which offer 

 certain peculiar characters not observed by us in other American 

 specimens. The most noteworthy features are: The extremely 

 scant, skeleton-like foliage, the large size and the peculiar serrate- 

 alternate apices of the fronds. The specimens may be character, 

 ized as follows: 



Rhizome rather slender, creeping, densely clothed with light 

 brown spreading chaff; stipe 5-8 inches long, pale green, smooth; 

 lamina very dark green above, decidedly bluish green below, 6-1 1 

 inches long ; pinnte distant from once to twice their width, each 

 tapering from its middle to a somewhat acute (occasionally sharp- 

 ly acute) apex, base broadly decurrent, veins sinuous and promi- 



♦Published by permission of the Secretary of the Smithsonian Institu- 

 tion. 



