380 FUNGOUS DISEASES OF PLANTS 



may be produced. Infection takes place through the young wheat 

 seedling, and the spores are very generally distributed by means 

 of the seed. 



Control. Bunt of wheat has very generally been successfully 

 treated by the methods recommended for oat smut. The formalin 

 treatment is preferred. In applying this method, however, some 

 prefer to sprinkle the wheat with the formalin solution (1 pint to 

 30 gallons) rather than to soak the seed. 



VIII. TILLETIA: OTHER SPECIES 



Tilletia Tritici (Beij.) Wint. This species also occurs upon the 

 wheat and was long considered to be merely a spiny or reticulately 

 marked form of Tilletia fcetens. Experiments have demonstrated 

 that the fungi are distinct. This species is less frequently found, 

 but when present it produces practically the same effects as those 

 described for the fungus last discussed. It sometimes occurs in 

 conjunction with Tilletia fcetens . A microscopic examination per- 

 mits an easy identification, since the reticulations on the wall of the 

 spore are marked in this species. The spores are very nearly equal 

 in size to those of the preceding and measure 16—22 \x in diameter. 



Tilletia horrida Tak. This fungus occurs in the ovaries of the 

 cultivated rice, and it is now widely distributed in the United States 

 as well as in the Orient. It is concealed by the enveloping blossoms 

 and is not readily observed in the field. The spores are subspherical, 

 measuring 22-33 A* m length. A band of scales 2-4 /x in width, 

 due to the thickenings in the outer hyaline wall, is generally evident. 



Tilletia corona Scrib. This species occurs upon plants related 

 to the rice, namely, members of the genus Leersia, and it is 

 common upon these plants in their natural habitats in the south- 

 ern states. 



IX. ENTYLOMA 



Entyloma Physalidis (Kalchb. & Cke.) Wint. The smut fungi 

 of the genus Entyloma are not commonly productive of conspicu- 

 ous deformities. In the case of Entyloma Physalidis pale spots 

 are produced upon the leaf of the ground cherry, or love-apple 

 (Physalis pubescens). The spores are intermediate in size, 10-16 fi 

 in length, and they are situated in small masses, or beds, scattered 



