PLATE i 
A. —Result of a smut explosion. Machine of W. J. Grier, near Colfax, Wash., a few 
hours after the explosion, August 12, 1915. By hard fighting the sacked grain on the 
right was saved, but the machine and straw stack were burned. Hundreds of thrashing 
outfits and thousands of bushels of wheat have been destroyed in the Pacific North¬ 
west due to fires following explosions of smut dust (bunt spores), which bum like 
powder. 
B. —Morphological effect of bunt on wheat heads. The three on the left are Alaska, 
the others Fortyrtold. Heads of each variety from left to right contain normal seed, 
both normal seed and smut balls, and only smut balls. In Alaska the parasite causes 
the awns to fall but dwarfs the head instead of stimulating increased length as in 
Turkey and Hybrid 128. (See PI. 2, A.) The head length of Fortyfold is not affected, 
but the spikelets on the infected heads stand out more nearly at right angles to the 
rachis. 
(480) 
