96 



SMUT OF WHEAT, 



threads and cells, and this mass at length gives rise to an im- 

 mensely large number of spores, which quickly become black in 

 colour, burst through the tissues, and so reach the outside air. 

 The fungus always grows so luxuriantly in the ears that nothing 

 is ultimately left of the part which should bear the grain but a 

 few dry vegetable threads, which are speedily torn apart, and this 

 wreck of what should be the ear is soon carried away by the 

 wind. As a rule, the ears, whether of wheat, oats, or barley, are 

 totally destroyed by the fungus. 



(© 





® ^ %^ (f* 



X'400 



T/ie spores or seeds of the Smut fuiigiis (G) enlarged 400 diameters ; 



other fungus spores enlarged to the same scale at I and J ; and 



Smut spores germinating, enlarged 1,000 diameters. 



The particles of the black powder are excessively minute in 

 size. If they are magnified 400 diameters, they are seen as 

 at G. An idea of their extreme smallness may be gained by 

 comparin_^^ them with a seed or spore of the potato fungus, illus- 

 trated to the same scale at /, or with a seed or spore of the 

 putrefactive mildew of onions, shown to the same scale at J. 

 Two hundred of the spores of the Smut fungus could find ample 

 room inside a single spore of the onion fungus, y, named Perono- 

 spora Schkideniana. Owing to their extraordinary smallness, the 

 spores of the Smut fungus find their way everywhere ; they are 



