rgtt] PRITCHARD—DISSEMINATION OF PUCCINIA 185 
would also appear to indicate that the spores are not commonly 
borne very great distances by the wind. 
Little or nothing has been done in the past to test the possible 
infection of sprouting cereals by means of germinating teleuto- 
spores from the soil. When buried in moist earth it is not even 
known whether teleutospores can produce germ tubes or promy- 
celia. A striking fact in connection with the possible infection of 
seedlings by teleutospores was observed in our field work. Our 
breeding ground, in which we produced an abundance of rust 
annually as described above, consisted in 1907 of three parts 
which, however, were nat separated by paths or any visible marks. 
The whole west half had grown three successive crops of rusted 
wheat (1905-1907); all the east half except a narrow strip on the 
north end grew rusted wheat in 1905 and 1907, but produced a 
crop of flax in 1906; the remainder was in sod until 1907, when it 
was planted to wheat. The rusty wheat instead of being removed 
from the ground was always plowed under. The same varieties, 
except some of Farrer’s wheat which was not taken into account, 
were planted on all three areas at the same dates. The soil was 
equally level and very fertile. All the wheat was inoculated alike 
during the spring and summer of 1907, yet shortly before harvest 
the three parts were separated quite distinctly by lines of rust 
demarkation, the amount of rust varying with the number of 
crops of rusted wheat grown upon each area. Whether these 
results are due to the different quantities of teleutospores in the 
soil of the different areas or not cannot of course be definitely 
stated, but they are at least suggestive of the need of further 
experiments in this direction. If the perpetuation of the wheat 
rust in the absence of the barberry is due to the teleutospore 
infection of the germinating seed, variation in the time of seeding 
might easily account for the annual variability in its prevalence. 
The further possibility that rust may be carried in the seed 
itself is certainly also to be considered. Teleutospores and myce- 
lial fragments of P. graminis are often present in abundance in 
the pericarp of wheat grains, and can frequently be recognized by 
the appearance of pustules, as will be described later. Early in 
the spring of 1905 about 60 wheat grains with such contamination 
