ECONOMIC IMPORTANCE OF FUNGI 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 life 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: 
