BROOKLYN 
Boa ANT “G ARap: EIN 
RECORD 
Vou. XIII JULY, 1924 No. 3 
THE SMUTS OF CEREALS: THEIR NATURE, ECO-— 
NOMIC IMPORTANCE, AND THE SIGNIFI- 
CANCE OF RECENT DISCOVERIES 
The demonstration of the existence of specialized races in the 
smuts of the cereals is a fact of fundamental significance. The 
restriction of physiologic races of parasitic fungi to particular hosts 
has been long recognized among the rusts, powdery mildews, and 
other groups of fungi. A similar condition also has been demon- 
strated for the anther smut which attacks various members of the 
pink family. 
So far as the smuts of cereals are concerned, it has been more 
or less generally assumed that physiologic specialization did not 
occur. A new light, however, is thrown upon the investigation of 
these destructive diseases by the discovery, at the Brooklyn Botanic 
Garden, of distinct races of the covered smut of barley in a single 
collection of material. In this particular case, the diseased heads 
of two varieties of barley were collected together, but experiments 
revealed the fact that while the smuts on the two varieties were 
indistinguishable on the basis of ordinary morphological characters, 
they did differ very strikingly in their physiologic behavior. They 
proved to be two well-defined races, each with a specific capacity 
for infecting definite varieties of barley. Similarly, distinct races 
of both loose and covered smuts of oats also have been discovered. 
In this case the original material of the smuts came from widely 
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