xxx.] BUNT OF WHEAT. 247 



these cracks a black powder emerges. On cutting affected 

 seeds in two, the outer coat of the grain is found to be 

 weak and brittle, and its whole inner substance a mass of 

 black powder, which has replaced the natural inner farina- 

 ceous material of the grain. On crushing bunted wheat 

 between the fingers the black pulpy powder feels soft and 

 greasy, and a foetid odour resembling decaying fish is 

 dispelled ; hence the popular name, stinking-rust. One 

 of its old botanical names is Uredo fcetida, Baeur. Bunted 

 grains do not occur as isolated examples in the ear ; the 

 rule is that every grain in an affected ear is bunted. 

 When these bunted grains are ground into flour their 



FIG. 115. 



Spores of the Bunt fungus, Tilletia Caries, Tul. 

 Enlarged 400 diameters. 



presence is made known to the miller, not only by the 

 black streaks they cause in the white flour, but also by the 

 disgusting odour which arises at the time of crushing. 



The black powder, when placed under the microscope 

 and magnified 400 diameters, is seen as at Fig. 115, one 

 mass of beautiful brownish spores, with a few fine mycelial 

 threads, to which some of the spores will be seen still 

 attached ; the supporting threads are best seen in young 

 examples, for as the fungus approaches maturity, the 

 threads break up into dust and perish. The spores are 

 spherical, or sometimes slightly oval, reticulated and 

 slightly spinulose, reminding a microscopist of pollen- 

 grains belonging to the Campanulacece, the colour of 

 course being different. They are so small that a single 



