GRASSES OF IOWA. 213 



outer half of the leaf, and sometimes is interrupted and forms 

 spots of various sizes and shapes. The spots, by increasing in 

 size, become confluent, and thus a leaf, at first spotted, may 

 soon become uniformly discolored. The discoloration results 

 from the death of the leaf tissues and the destruction of the 

 green coloring matter of the leaf cells, the affected parts 

 appearing to the observer like so much dead leaf. " 



Stewart* states that the E. inconsjncuum on Long Island 

 must be regarded as an enemy of considerable importance. 

 Both sweet and field corn suffered in some cases so severely as 

 to materially lessen their value for fodder. The farmers 

 attributed the cause of the disease to a period of unusually hot 

 weather which prevailed during the month of August. Thax- 

 terf states that it is also injurious at times in Connecticut 

 where it is known as "white blast of Indian corn. " It is com- 

 mon at times in Iowa and does much injury. 



Later Briosi and Cavara distributed a fungus on corn with 

 a description of Passerini's H. turcicum. In 1891 one of us gave 

 an account of EehninthosporiuTn graminwn, Rabh., on barley in 

 which reference was made to the fungus on corn. J. B. Ellis, 

 to whom the fungus was submitted states that it is identical 

 with the corn fungus After a careful examination of the 

 material at hand we are of the opinion that these fungi are dif- 

 ferent. The Italian fungus has not been observed here, but an 

 account is given to complete the list of diseases occurring on 

 corn. In the Italian disease the spots are sharply limited 

 across the veics, one to three inches long, one-sixteenth to one- 

 eighth of an inch wide. The dead tissues have the appearance 

 of dead corn leaves when ripe or affected by frost and produce 

 premature wilting. The surrounding green is in strong con- 

 trast. Over the dead areas may be seen small brown clusters, 

 the hyphae and spores. 



One or more of the fruiting hyphae make their way through 

 the opening of the stoma. These come from a colorless myce- 

 lium. The conidiophores as well as the spores are brown. 

 The latter are large, 8-100" in length, 20-24" in width. This 

 fungus is often associated with Cladosporium fasciculatum Corda 



*Rep. Geneva N. Y. Agrl. Exp. Sta. 15: 452. pi. 32. f. 2. 1896. 

 tRep. Oonn. Agrl. Exp. Sta. 1889: 171. 1890. 



