ECONOMIC IMPORTANCE OE EUNGI 



299 



stem, fruiting in the tissues, and commonly destroying 

 the kernel of grain. The innumerable black spores form 

 a sooty powder — whence the common name of "smut." 



Fig. 221. — Corn-smut {Ustilago.maydis). on stalk, tassel, ear, and leaf of 



Zea Mays. 



286. Rusts. — The Ufe history of the wheat rust {Puc- 

 cinia graminis) was outlined in Chapter XIX. This 

 fungus has not only caused millions of dollars worth of 

 damage to the wheat crop of the world but has been the 

 cause of legislative enactments. As early as 1760 there 

 was passed in Massachusetts "An Act to prevent Damage 

 to English Grain arising from Barberry Bushes." This 

 act read, in part, as follows : 



"Whereas it has been found by experience, that the Blasting of Wheat 

 and other English Grain is often occasioned by Barberry Bushes, to the 

 great loss and damage of the inhabitants of this province: 



