HEMIBASIDIOMYCETES 379 



VII. BUNT, OR STINKING SMUT OF WHEAT 



Tillct'ui fa-tens ( 15. Ov C.) Trel. 



KELLERMAN, W. A., and SWINDLE, W. T. Preliminary Experiments with 

 Fungicides for Stinking Smut of Wheat. Kan. Agl. Exp. Sta. Built. 12 : 

 27-50. //. /. 1890. 



KELLEK.MAX. W. A. Second Report on Fungicides for Stinking Smut of 

 Wheat. Kan. Agl. Exp. Sta. Built. 21: 47-72. 1891. 



Distribution and symptoms. The above species is the more 

 commonly distributed smut of this family upon grain in the United 

 States, and while very commonly found in greater or less abun- 

 dance, it is nevertheless entirely absent from some considerable 

 wheat-growing regions. On the other hand, in portions of the 

 Northwest, and extending also into Canada, there are regions in 

 which the losses from this fungus have amounted to from one half 

 to two thirds of a crop. The fungus affects the various varieties of 

 wheat, but is not found upon any other grain. Little definite infor- 

 mation, however, has accumulated concerning the susceptibility of 

 different varieties to attack. The abundance of disease in certain 

 regions would not seem to be greatly influenced by climatic con- 

 ditions, but is probably very largely due to unfortunate practices in 

 seed selection and to continuous cropping with wheat. The pro- 

 duction of spores in the tissues of the host is confined very largely 

 to the ovule sacs, at maturity the kernels being the chief seat of the 

 spore masses. The spores are permanently concealed by the glumes 

 which envelop the kernels ; but smutted heads are more or less 

 recognizable on account of a slight difference in color and a some- 

 what emphasized flaring habit of the spikes, due perhaps to slightly 

 larger size of the infected kernels. The spores give rise to a pene- 

 trating and disagreeable odor, which becomes very evident in the 

 bin or during the milling process. In general, all of the kernels of 

 a spike will be infested. 



The fungus. The spores are brown in color, usually oblong to 

 spherical in form, with a smooth wall, varying considerably in size, 

 extremes being more than from 1 6 to 25 /x in length. The germi- 

 nation of the spores of this species conforms well to the description 

 given for the whole family. The acicular or needle-shaped sporidia, 

 which are produced in the form of a crown on a short, continuous 

 promycelium, frequently unite in pairs, and secondary sporidia 



