OBSERVATIONS ON THE WINTERING OF GRAIN 
RUSTS. 
A. H. CHRISTMAN 
The manner in which grain rusts pass the winter in northern 
climates and in regions where the barberry is wanting, is still 
considered an open question. Eriksson and Henning (1), while 
they record the germination of uredospores collected during the 
winter and early spring, conclude that these spores and the 
mycelia producing them play no important part in perpetuat¬ 
ing the fungus. As is well known, they hold that rust may be 
transmitted as a nonhyphal, so called, mycoplasm in the cells 
of the host. It is quite possible that their adherence to the my¬ 
coplasm hypothesis on other grounds has biased their judgment 
on the question of the ability of uredospores and mycelium to 
pass the winter. Ward (2) rejects the mycoplasm hypothesis 
entirely and probably most mycologists regard it with great 
skepticism. 
On account of the position taken by Eriksson and Henning, 
it may be well to review some of the earlier observations re¬ 
corded as bearing on this question. As early as 1875 Kuhn (3) 
found uredospores of P. graminis Pers. in the early spring near 
Halle, in Germany, and in same year Nielson * 2 * 4 concluded that 
in Denmark, P. rubigo-vera D. C., passes the winter as a myce- 
lEricksson and Henning,—Die Getreideroste Stockholm, 1896. 
2 Ward, H. M. On the Histol. of U. ddspersa, Erikss., and the “My¬ 
coplasm” Hypothesis. Phil. Trans. Hoy. Soc., Yol. 196, p. 29, ’03. 
3Uber die nothwendigkeit eines Verbotes der Pflanzung und Anlage 
der Berberitzenstrauches. Kwhn J. Landw. Jahrb. Bd. 4, 1875, p. 399. 
4 p. Nielsen,—De for Landbruget farligeste Rustarter og Midlerne 
mod dem. Ib., 1875, Bd. 1. 
