vit] Smuts 73 
CHAPTER VII 
SMUTS 
On walking through a cornfield just before the grain 
is ripe here and there black ears, known as smuts 
or Black Heads, may be noticed, as they are easily 
seen by contrast with the colour around them. The 
blackening of these ears is caused by various fungi and 
it is from this black colour that they derive their 
name “‘smuts.”” They may be found on barley, oats, 
wheat, and also on a number of grasses. There are 
many kinds, most of which belong to the genus Usitilago. 
A host plant may have more than one species capable 
of attacking it, but each smut has its own particular 
host. Those attacking barley cannot infect the oat 
plant, neither can those found on oats attack barley. 
In place of the grain which is present in a healthy 
plant, the blackened ears contain a dark brown powdery 
mass (this powder is very dark and causes the ears to 
look black). It consists of a large number of almost 
spherical bodies, which are the spores of the fungus. 
The development of these can be watched in a hanging 
drop of water. After a time a small germ tube is 
sent out. This does not grow very long but becomes 
divided up into four cells by three cross walls. 
From the upper portion of each of these cells a 
process is given off, which eventually becomes divided 
from the cell producing it. These are secondary 
spores and in such places as manure heaps, where food 
supply is abundant, they increase in number by 
budding, but it is sufficient for our purpose to know 
that the plants are infected by means of these. 
