164 NATURAL HISTORY BULLETIN. 



habitat. Fruit begins to appear in June and continues until 

 September, or even later. The athyrioid character (like 

 so many similar characters of ferns) becomes obscured as 

 the fern grows older, and the sori then sometimes almost 

 cover the back of the frond, especially in fronds with 

 narrow divisions. The specimens from Jackson county 

 collected by Prof. Macbride in 1883 show this very well. 

 The following counties are represented: Louisa (P. C. 

 Myers, Aug., 1897, sterile); Muscatine (July, 1895, 

 sterile) ; Johnson (July, 1880, well-fruited) ; Jones (J. E. 

 Cameron, July, 1895, fruit nearly mature); Jackson (T. 

 H . Macbride, Aug. , 1883 ; well-fruited and with un- 

 usually narrow segments); Delaware {T. H. Macbride, 

 Aug., 1883, fruit advanced) ; J. E. Cameron, Oct., 1897, 

 with old fruit); Allamakee (T. E. Savage, June, 1899, 

 with young fruit) ; Cerro Gordo (July, 1899, shows some 

 mature fruit); Winnebago (July, 1896, fruit scant); 

 Emmet (Sept., 1895, fruit well advanced) ; Webster (July, 

 1897, sterile); Polk (pupils of E.Des Moines High School, 

 no date; well-fruited); Ringgold (July, 1890, sterile); 

 Calhoun (G. B. Rigg, no date, sterile); Pottawattamie 

 (J. E. Cameron, June, 1897, sterile) ; Lyon (July, 1899, 

 sterile) . 



Athyrium thelypteroides (Mx.)Desv. 



Locally rather common in the eastern part of the State. 

 It grows in shady places, in the lower parts of wooded 

 ravines, etc., preferring rather moist places, and begins to 

 fruit in August. Mature fruits show apparent diplazioid 

 characters, and the species has been referred to 

 Diplazium .* An examination of young fruits however 

 shows very clearly that the seemingly two sori are one 

 reverted in athyrioid fashion. It will probably be neces- 

 sary to similarly remove other species of Diplazium to 



*Underwood, /. c, refers it to the sub-genus Athyrium. 



