Christman—Wintering of Grain Rusts. 99 
lium in the leaves of grain. He gives it as his opinion that 
the rust retains its vitality so long as the leaves of the host 
remain green. Blomeyer, 1 in 1876, found uredospores of P. 
graminis Pers. on grain near Leipzig in May and maintains 
that these had matured too early to he attributed to infections 
from an aecidium of that season. In England, Plowright 2 
found open pustules of uredospores of P. graminis on Triticum 
repens on December 31, 1881, and on the same grass again in 
March of the next year. Yon Thiimen, 3 in 1886, also observed 
that in Austria uredospores continue on certain grasses through¬ 
out the entire year. 
The investigators mentioned above give us no data as to the 
minimum temperatures in the seasons in which their observa¬ 
tions were made. It will be remembered, however, that the 
minimum temperature for the winter in Denmark, Germany, 
and Austria is about the same as that of Southern Illinois or 
Kentucky, while that of England is about the same as that of 
Tennessee. 
Similar investigations were undertaken by H. L. Bolley 4 at 
Lafayette, Indiana. At various times during the winter of 
1888-1889, he found healthy mycelium within the leaves of in¬ 
fected wheat plants. During the first warm days of March there 
was a general outbreak of uredospores. Bolley concludes that 
wheat rust passes the winter in Indiana as a mycelium within 
the host. 
Ericksson and Henning,, 5 at Stockholm, Sweden, where the 
winter temperatures are similar to those of Madison, Wisconsin, 
record the finding of viable uredospores of Puccinia dispersa in 
abundance on November 29th, 1891, and again on the same 
plants, April 2nd, 1892. The postules then disappeared and 
fresh ones were not again found until April 30th. Viable 
1 Blomeyer,—Vom Versuchfelde des Landwirthschaftlichen Institutes 
zu Leipzig. Landw. Bd., 25, 1876. 
2 Plowright,—The connection of wheat mildew with the barberry 
aecidium. Gardner’s chronicle. Series 2, Vol. 18, 1882. 
3 Von Thiimen,—Die Bekampfung der Pilzkrankheiten unserer Kul- 
turgewachse. Wien., 1886. 
4H. L. Bolley, Wheat rust. Bull. Agr. Exp. Station of Indiana. No. 
26, 1889. 
5Loc. cit 
