THE AMERICAN BOTANIST 87 



set up the infection en the barberry again. From the fore- 

 going it would seem that all that is required to forever rem ve 

 the danger from rust is to remove the barberry, thus breaking 

 its life cycle, but the rust is not so helpless as all that. If no 

 barberry is at hand the rust merely omits that part of its life 

 cycle and sets up its infection directly upon the wheat. In 

 India and Australia, where the barberry does not grow, the 

 wheat rust is well known. Removing the barberry, then, is 

 only one step in the effort to curb the pest. A second inter- 

 esting fact is that the further South one goes the less is the 

 barberry concerned in spreading the wheat rust. In warm 

 regions the summer spores survive the winter and propagate 

 the rust, and the autumn form or black rust, if it occurs, does 

 not seem to affect the barberry. In cooler regions the bar- 

 berry is often heavily rusted in spring, though there may be 

 extensive areas where it is not affected. The connection cf the 

 barberry and the wheat rust has been suspected for a very long 

 time. Laws were frequently made against the shrub, but it 

 has continued to hold its own. A half century ago, the State 

 of Massachusetts ordered its extermination. 



From the facts here presented, it is very apparent that 

 while the barberry is not the only method by which wheat rust is 

 spread, it may on occasion contribute to this end and should 

 be rooted out, especially in the vicinity of wheat fields and 

 other cereal crops. In cities and towns, far removed from 

 grain fields, it is probably not a very great menace, but since 

 it is not especially ornamental it should be replaced as soon 

 as possible by less dangerous and more decorative shrubs. 

 Spiraeas, hydrangeas, golden bell, snowball, ninebark, mock 

 orange, rose-of-sharon, lilacs and an immense number of other 

 floriferous shrubs will grow wherever barberry will, and are 

 far superior to it. Lastly, the Japanese barberry, so exten- 

 sively planted for hedges, is not affected by the rust and need 

 not be disturbed. 



