34 BOTANICAL GAZETTE [ JANUARY 
one of the most respected authorities in this subject, Professor 
Julius Kihn, of Halle, proclaimed the opinion in an official report 
of 1875 that a distance of 100 meters between the barberry bush — 
and the grain field may be considered sufficiently protective. 4 
During the last few years many experiments have been se 
point to the same conclusion. They show that the matter 0 
in a like spread in summer from barberry, etc., to the Gramine& 
By observation on the rust’s appearance upon 7yiticum repens at 
different distances from a barberry bush it has been prove 
beyond doubt that the influence of the bush does not extend 
farther than 10 to 25 meters. 
For these reasons it was insisted upon in the circular, whicl 4 
a short time since was sent out to several of the officials i 
Sweden, that no barberry, wild or cultivated, be permitted 
grow at a distance less than 2 5 to 50 meters from a grain field 
5. Lhe germinating power of the winter spores (teleutospores, 
depends upon certain external conditions, and is restricted to a shor 
period of time. 
The winter spores of black rust are capable of germinatiol 
in spring only in case they have been exposed to quite natural” 
conditions of cold, snow and rain, during the previous winter. 
and consequently rusted litter preserved in a barn or in a sta 
is not to be regarded as dangerous. This has been fully demon: 
Strated in the results of the fir 
: st four years as given in the 
detailed report. 
Observations and experiments made during the current yé 
e brought to light still another matter of interest concerning 
the germinating power of the spores. It appears that only th 
hav 
