184 IOWA ACADEMY OF SCIENCE Vol. XXVI, 191'J 



Studies certainly show that E. Macoiinii is more commonly infected 

 with P. graminis than any other Elymus, and that it ranks with 

 Hordcum jubatmn, Agrostis alba, Phlcum pratense, Agropyron 

 tcnerum, A. rcpens and A. Smithii in being an important host for 

 P. graminis. 



Asprella Hystrix Willd. This grass is widely distributed in Iowa 

 from Hamburg in Fremont county to Rock Rapids in Lyon county 

 on the west and across the state from Keokuk in Lee county to New 

 Albin in Allamakee county ; also abundant in western Illinois north 

 to Galena, and to La Crosse, Wisconsin, west to Big Stone Lake in 

 Minnesota and to eastern South Dakota. It is found in woods and 

 borders of woods. Stakman and Piemeisel report the rust on the 

 species from St. Paul and Ramsey county, Minnesota, both P. gra- 

 minis tritici and P. graminis secalis. The strain found was less 

 virulent than the typical P. graminis secalis. On some of the grasses 

 they report a normal development naturally and when inoculated. It 

 must be a rare host for it in nature. The host is quite generally 

 free from fungus diseases, except the Phyllachora graminis, which is 

 common. 



THE RELATION OF WILD GRASSES TO THE BARBERRY 



I shall not attempt in this connection to give an extensive ac- 

 count of the relation of the various biologic forms of Piiccinia 

 graminis to the aecidium on the barberry. I will cite a few illustra- 

 tions which have come under my observation. 



Lake Mills Case — The Lake IMills region is a glaciated one in the 

 Wisconsin drift area, consisting of marshes and wooded areas inter- 

 spersed originally with prairie. At Lake Mills I found a barberry 

 hedge of 100 plants near the elevator on the premises of Mr. Opdahl. 

 The hedge was removed about June 29, .a month before my visit. 

 The Chicago & North Western Railway is adjacent to this lot and 

 the right-of-way of the railroad contains the usual wild grasses, 

 Hordeum jitbatimi, Agroypron Smithii, A. teneriim, A. re pens, 

 Agrostis alba, Phleum pratense and Elymus canadensis. A small 

 field of oats and barley adjacent to the railroad and 900 feet away 

 from the barberry bushes was badly rusted. The wheat and oats 

 were hardly worth cutting. The wild grasses mentioned also were 

 badly rusted in the vicinity. The rust on these grasses also occurred 

 for 300 feet from the barberry bushes, the infection gradually 

 diminishing up to 1,500 feet. The rust on a small patch of wheat 

 one-half mile away was not severe. It is certain that the barberry 

 influenced rust on the wild grasses to a considerable extent. 



