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separated sources. Further investigations may doubtless reveal a 
high degree of host specialization among these parasitic fungi. 
The Value of Cereals —The cereals are the most important food 
plants of the human race. Over practically the whole world some 
cereal, as wheat, oats, barley, rye, corn, rice, millets, and sorghums, 
supplies the basic food of the different peoples. All of these are 
grown in the United States, at least to some extent, and thus oc- 
cupy a very important place in the activities of the farmers. 
Since ancient times wheat has been a very important food crop. 
It constitutes the great bread crop of a large proportion of the 
human race. Somewhere in the world wheat is being harvested 
every week of the year. The total world production is about 3% 
billion bushels. Before the war Russia ranked first as a producer 
of wheat and the United States ranked second, producing about 
one fifth of the world’s total. Several European countries, as 
France, Hungary, and Italy, also grow large quantities. In India, 
Canada, Argentina, and Australia wheat growing is a very impor- 
tant phase of agricultural activity. The average annual per capita 
consumption of wheat in Canada is twelve bushels; in the United 
States, five and one half bushels; and in India, one bushel. Most 
European countries produce less wheat than they require for their 
needs and they obtain their surplus from the United States, Russia, 
India, Canada, Argentina, and Australia. 
From the standpoint of production corn or maize is our most 
important cereal. The average annual production for Ig10 to 
1914 was 234 billion bushels. The United States produced about 
three quarters of the corn crop of the world. Argentina, Brazil, 
and Mexico grow considerable quantities of corn. Although this 
cereal was unknown to Europeans before the discovery of Amer- 
ica, it is now grown extensively in other parts of the world where 
it is adapted. Some European countries, as Italy, the Balkan 
countries, Hungary, Spain, and Portugal, are important corn-pro- 
ducing regions. It is also grown in various parts of Africa and 
Asia. The chief use of corn is feed for hogs and cattle, and in 
this indirect way is of very great significance to man. However, 
a large quantity of corn is used directly for human food. 
Rice holds a very important place among the food grains of the 
