TILLETIA TRITICI 215 



side in a greenhouse on Kota wheat (Fig. 105) and also on Reward 

 wheat (Fig. 106). The first of the strains caused the grains to 

 become rounded-oval and the second elongated. However, the 



Fig. 105. — A difference in the effect of strains of two species 

 of Tilletia on Kota Wheat. The elongated smut-balls 

 on the left were produced by a strain of Tilletia laevis 

 and the more rounded ones on the right by a strain of 

 T. tritici. From greenhouse cultures made by W. F. 

 Hanna. Natural size. 



observations of Rodenheiser * and, more recently, Aamodt 2 have led 

 these workers to the. conclusion that the shape of the bunt balls 

 varies with different physiological forms and cannot be generally 

 accepted as a criterion for separating T. tritici and T. laevis. 



Fig. 106. — A difference in the effect of strains of two species 

 of Tilletia on Reward Wheat. The elongated smut- 

 balls on the left were produced by a strain of Tilletia 

 laevis and the more rounded ones on the right by a 

 strain of T. tritici. From greenhouse cultures made by 

 W. F. Hanna. Natural size. 



Further comparisons of the differences between the bunt balls of 

 T. tritici and T. laevis based on experiments made with inocula 

 derived from monosporidial cultures seem desirable. 



1 H. A. Rodenheiser, he. cit. 2 0. S. Aamodt, in litt. 



