218 GRASSES OF IOWA. 



used their material with such work as has been done from time 

 to time during my connection with this experiment station. 



CORN SMUT (USTILAGO MAYDIS). D C. 



For more than a century this troublesome fungus disease 

 has been known. The first reference to it was made by Aymen* 

 in 1760, who records the disease on the tassel of corn. In 1806 

 it was described by De Candollef as Uredo segetum. Var. mays- 

 zeae. D. C. Burger,]: ia his work on corn, gives a short 

 account of the f angus. Bonafous,§ in his treatise on corn, gives 

 the most complete of the early accounts of this disease. 

 Kuehn, || Tulasne,^ Meyen, **Brefeld, f f Fischer de Waldheim, tt 

 and a host of other writers have contributed to an account of 

 corn. For a good bibliography as well as abstracts and con- 

 clusions of these writers we must refer to a paper by Hitchcock 

 and Norton. §§ These writers have followed Magnus in adopt- 

 ing the name of Ustilago mays zeae (D. C.) Magnus, but the 

 name in common use, that of Ustilago Maydis, seems preferable 

 and is adopted in this paper. 



General characters. — Corn smut makes its appearance when 

 the plant is three or four feet high, a little before the time of 

 flowering, although in some cases it is not observed till the ears 

 form. Careful search will show that many leaves, as well as 

 the nodes, are infested before the ear forms. In the leaf, small 

 wrinkled patches appear. These are frequently reddish in 

 color; later assume a glossy white color, and as it becomes 

 older changes to a black sooty mass. The lower nodes are 

 especially infested; also where the leaf joins the sheath. The 



*Rec. sur. les progres et les causes de la Nlelle. 7". 



i-Fl. Fr. 2: 596. 



$Abhandling uber Mais. 242-43. 1809. 



SHlstorle Naturelle. Agricole et economique du Mais. 94. 1836. 



CDle Krankheiten der Kulturgewachse. 70. 18.59. 



IMemolre Sur les Ustilaglnees comparees aux Uredlnees. Ann. Sci. Nat. III. 

 7: 83. 18J7. 



**Pflanzen Pathologle. 102. 1841. 



ttUntersuchungen aus dem Gesammtgeblete der Mykologle. Also Neue Unter- 

 suchungen uber die Brandpilze und Brandkrankhelten. II Nachrlchten aus dem 

 Klub der Landwlrthe zu Berlin. 1888. 



*$Coutr. to the biology and history of the development of the Ustllaglneae. Rep. 

 N. Y. Agrl. Soc. 1870: 280. Translated from Pringsh. Jahrb. Wlss. Bot. 7: 61. 



SSBuU. Kans. Agrl. Exp. Sta. 62. 190-197. 1896. See, ivlso, Corda. For contribu- 

 tions to the knowledge of the different kinds of brands in the cereals and blight in 

 grains, by Corda, translated by Smith, 19. pi. 3 f. 1-2. Emmons" Agrl. of N. Y. 2: 265. 



