UTAH ACADEMY OF SCIENCES 113 
Summing up, these are some of our conclusions and 
our present position. First. Besides infection of the seed- 
ling, still other forms of infection exist, such as blossom in- 
fection of wheat, barley and oats, by the loose smuts, and 
infection of young leaves, as in the water plants, a point 
previously overlooked. 
Second. In general, only the youngest embryonic tis- 
sues of any host plants are the ones attacked by the germs 
of infection. 
Third. Experiments on infection of maize smut have 
proved clearly that the large host plants in the process 
of development and formation expose in different places, 
for example the leaves and the flowers, young embryonic 
tissue which can be attacked by infection germs. 
Fourth. A similar condition to that of the maize hap- 
pens in water plants where the embryonic tissue of devel- 
oping leaves is affected. 
Fifth. In the loose smuts of wheat and barley and 
the anther smut of Melandryum, the matter is essentially 
different from the cases of corn and water plants. Here 
the disease does not develop in the parts in which infec- 
tion takes place. The result of infection is shown only after 
a long period of incubation during the winter time and at 
the time of unfolding of the inflorescence of the plant the 
following year. While the idea formerly prevailed that 
only seedling infection occurred, we have now come to 
realize that at the flowering time the ovules and stigmas 
offer assailable tissues for the germs of infection and that 
this takes place in these embryonic parts. 
Sixth. Accordingly, in the occurrence of smut dis- 
ease in our grains, we must reckon with two places of 
infection, quite independent of each other, first the young 
germinating seedling, second the blossoms. We must con- 
sider that in separate cases both forms of infection may 
be effective at the same time, but first one and then the 
other will have the ascendency. In judging of the natural 
spread of smut fungi and smut diseases, these recently ex- 
plained facts are of direct value. Also they are of the ut- 
most value when it comes to a consideration of the con- 
trol of these diseases. 
