54 
culture sets were different from the parental cultures. The varia- 

tions, however, generally fell within a range characteristic for a 
given race. In some cases a set of cultures of a race proved to be 
quite uniform, while in other cases considerable dissimilarity was 
noted. Selections of cultures of several races frequently exhibited 
more uniformity than existed within individual sets of the different 
races. Neither loose nor covered smut can be separated on the 
basis of its behavior in artificial cultures. Further, the physiologic 
races cannot be definitely distinguished by these means. 
In 1933, combinations of cultures were made involving 13 single 
conidial isolations of loose smut with 3 of the covered. Definite 
races of both smuts were used throughout. The various combina- 
tions were used to inoculate Gothland and Monarch oats, the 
former being highly susceptible to the loose smut but resistant to 
the covered, while the latter shows the reverse type of reaction. 
At harvest time it was found that 5 of the culture combinations had 
produced infection of the loose smut type, 3 on Gothland and 2 
on Monarch. 
The chlamydospores collected on these plants were used to in- 
oculate oat varieties in 1934, The loose smut collected on Goth- 
land was found to produce smutted plants, some of which were 
identified as loose smut and others as the covered. The loose smut 
type appeared on Gothland and similar reacting varieties, while the 
covered smut occurred on Monarch. The loose smut collected on 
Monarch produced a similar type on Gothland, and also produced 
a covered smut type on this same variety. 
Again, all smut was collected from the host varieties and used 
in a series of experiments in 1935. In general, the results indi- 
cated that many of the loose smut collections produced infections 
of the loose smut type on Gothland, while some of the covered 
smut collections produced covered smut only on Monarch. A few 
cases, however, were noted in which Monarch was found to be 
severely infected with a loose smut type and, further, a covered 
smut type of infection was found to occur on Gothland. The evi- 
dence thus indicates that, through the combination of the original 
cultures, new types of smut have arisen—a loose smut capable of 
infecting Monarch, and a covered smut capable of infecting Goth- 
land. 
