45 
wide range of conditions. The highest infection secured was 
g1.6 per cent., although infections above 80 per cent. were fairly 
common, Similarly, the Red Amber Sorgo proved to be very 
susceptible to spores from sorgo, the highest infection obtained 
being 84.6 per cent. In 1925 there was no infection of sorghum 
with spores from corn, nor infection of corn with spores frorn 
sorghum. During the past season, however, some evidence was 
obtained to indicate that the smut from corn could pass over 
onto sorghum, since in a few experiments the sorgo inoculated 
with spores from corn were infected, the highest percentage being 
20 per cent. Similarly, a few corn plants inoculated with spores 
from sorghum were also infected, the highest percentage being 
10.7 per cent. in one experiment. These results indicate that to 
some extent, at least, the smut from one host can pass over onto 
the other. 
Tris Diseases 
The disease of Iris, which is characterized by the destruction of 
the fibrous roots, proved to be very severe during the past season, 
a large number of the bearded varieties being severely injured 
and prevented from blooming. The disease is characterized by 
the decay of the fibrous roots, which prevents the plant from 
getting water and essential nutrients from the soil. As a rule 
the rhizome remains fairly healthy. Miss Marjorie Swabey, 
Research Assistant, carried out a large number of experiments 
with a view to finding a remedy for the disease. Several ot 
them proved effective. They were, however, all radical, as they 
involved the lifting of the rhizome, its treatment and subsequent 
replanting. While the variety may be preserved by this process, 
yet the operation is destructive to bloom during a particular sea- 
son. It was found that if the rhizomes were lifted, cleaned and 
exposed to the sun for a few days, and then replanted in a new 
soil they generally put out roots and leaves and fully recovered 
from the trouble. 
Cryptogamic Herbarium 
Only a few additions were made to the Cryptogamic Herbarium 
during the past year. The last two centuries, containing two 
hundred specimens, of the North American Uredinales were 
