1882.] FUNGI INJURIOUS TO VEGETATION. 165 



the possibility of this, have, on their part, erred in asserting that 

 the barberry could have no influence on the wheat. This is one of 

 many illustrations of the fact that a popular notion has a real foun- 

 dation, and a scientific investigation, while it shows this to be the 

 case, often demonstrates the popular reasoning to be at fault. Thus 

 the popular notion that the barberry had an unfavorable effect 

 upon wheat was right; ascribing this effect to the pollen of the 

 barberry flowers was wrong, and it remained for the scientific in- 

 vestigation to show the real relation between the barberry-bushes 

 and the wheat rust. The fact that the barberry does not grow in 

 all places where rust occurs on wheat, has been presented as dis- 

 proving the relation between the two, but it must be remembered 

 that we are dealing with fungus spores, excessively minute bodies, 

 so light and airy that they go with the wind and may be carried 

 to great distances. "We must not overlook the fact that a single 

 "cluster cup "may produce half a million of these spores, and 

 that there may be a thousand of these "cups" upon a single bar- 

 berry bush. I have seen whole rocky hillsides devoted exclusively 

 to the growth of these "cups," so to speak, where the barberry 

 which clothed them was so affected as to give a rusty color to the 

 entire landscape. Such a locality is a hot-bed for the propagation 

 of wheat rust for the whole country. 



Remedies. — The destruction of the barberry in wheat-growing 

 districts seems to be imperative. It has been recommended for 

 an ornamental hedge, and- is well suited to this use, but there are 

 other shrubs quite as ornamental for this purpose which have not 

 the unfortunate failing belonging to the barberry. No one should 

 willingly cultivate a shrub which may injure his neighbor's crop 

 of wheat. By destroying the barberry we materially reduce the 

 means by which the rust is propagated. The burning of the 

 wheat stubble will destroy the dark winter spores which carry the 

 pest over the winter season. It goes without talking that if we 

 kill all the rust spores there will be an end to the rust, and to do 

 this there must be concerted action on the part of all farmers by 

 destroying all barberry -bushes and all grain stubble. This is too 

 much to hope for until we are driven to it, and until then we may 

 expect the rust to make its appearance about the time the grain is 

 filling, and will be the most fatal if there is a series of showers 

 with alternate hot sunshine, thus providing the most favorable 

 conditions for the propagation and the development of the fungus. 

 These conditions, over which we have no control, will decide in a 



