166 NATURAL HISTORY BULLETIN. 



ing in shaded places on moss-covered rock, etc., usually 

 on or near limestone ledges. Fruiting specimens may be 

 found at all seasons of the year. All of the specimens in 

 the herbarium are well fruited, and most of them show the 

 proliferous habit. The following counties are represented: 

 Muscatine (T. H. Macbridc, Sept., 1882; Shimck, Oct., 

 1900); Johnson (Aug., 1881; Aug., 1893; Sept., 1897; 

 March, 1898. These are from different stations) ; Jones 

 (T. H. Macbride, Aug., 1895) ; Delaware (J. E. Cameron, 

 Sept., 1897); Winneshiek {T. E. Savage, June, 1899); 

 Dubuque (J. A. Anderson, July, 1900). 



Family PTEBIDIEJE J. Smith, Hk. Jour. Bot. (1841). 



Genus PTERIDIUM Scopoli.* 



Pteridium aquilixum (L.) Kuhn. 



This species, so common in the eastern part of the 

 State, is represented by a comparatively small series. It 

 grows in deep woods where its long creeping rootstocks 

 frequently send up fronds at intervals of two to four feet. 

 It begins to fruit in July, or even in June. The following 

 counties are represented: Muscatine (Oct., 1900, sterile); 

 Johnson (Sept., 1880; another without date); Delaware 

 (J. E. Cameron, Sep., 1897, sterile); Allamakee (T. E. 

 Savage, June, 1899, sterile); Winneshiek (T. J. Fits- 

 patrick, June 24, 1896, well-fruited) ; Winnebago (July, 

 1899, well-fruited). 



Genus PELL^A Link, Fil. Hort. Berol., p. 59,(1841). 



Peli^Ea atropurpurea (L.) Link. 



Locally rather common in crevices of rock on exposed 

 limestone ledges. New fruits are formed in June or July 

 and may continue all winter. The following counties are 

 represented: Johnson (July, 1880, well-fruited) ; Jones 



*On authority of Diels (1. c). 



