Cereals 



277 



That some intimate relation existed between the bar- 

 berry bush and the black-stem-rust of wheat was suspected 

 very early in the seventeenth century, and in 1660 a barberry 

 eradication law was passed in France, while between 1726 and 

 1779, Connecticut, Rhode Island, and Massachusetts did like- 

 wise. In 1818 Schroeter, a Danish school-teacher, published 

 many observations concerning; the relation of the cluster-cup 

 upon the barberry and the rust of grains. This relation was 

 finally definitely proved by De Bary in 1865, who, by sowing 

 the teliospores from the wheat upon the barberry, produced 

 the cluster-cups. 



Some rusts are closely limited in host range and can grow 

 on very few, perhaps on only one host ; others are able to grow 

 on various hosts. The host relation of several important 

 cereal rusts is shown in the following table : ■'^^ 



