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SECTION OF VEGETABLE PATHOLOGY. \ 381 
>. Zew and described as occurring intheear. Some peculiarities in the 
description led Link, Tulasne, and European botanists who have 
_ followed them to suppose that it was different from the European 
form. Tulasnetherefore called the American form Ustilago Schwein- 
_ w#zii, and in this he has been followed by Fischer de Waldheim in 
' his recent works. But Ravenel,* as early as 1848 (the year after the 
ublication of Tulasne’s paper), stated that Schweinitz’s and Tu- 
oe names were synonyms. 
In the practical study of smuts, Prevost appears to have been the 
first to gain any valuable results. In 1807 he made the first obser- 
vations on the germination of the spores and maintained that the 
smut as a parasitic fungus was the cause and not a mere accom- 
_ paniment of the disease. 
Meyen, in 1837, first studied the spore formation in the corn. His 
observations were partly confirmed by Léveille two years later. This 
was more fully made out by DeBary and published in 1853. In 1858 
Kiihn published the results of his investigations, which were quite 
complete as regards Indian Corn Smut. He left undetermined the 
mode of entrance of smuts into their host plants except of the bunt 
of wheat. This was discovered by Wolff for wheat smut and sev- 
eral other species, and soon afterwards by Kiihn + for Indian corn. 
This apparently completed the cycle of development, but it was left 
- for Brefeld to discover a mode of germination and growth wholly 
unsuspected. In previous attempts to germinate the spores they 
had been placed in water or a moist atmosphere. Brefeld sowed 
them at first by accident, in a nutrient solution, an infusion of 
manure. His mass of dry spores was accidently thrown to the floor, 
and a dust-like cloud of spores was scattered throughout the room. 
_ Some fell into a nutrient solution which was in use for other cult- 
~ ures and there germinated. This experiment was afterward re- 
| eated many times with the same result. They grew by budding 
ike yeast and could continue to grow in that manner for an indef- 
- inite period ; but when the nutriment was exhausted they would form 
mycelial hyphee in the normal manner. { 
(6) EXTERNAL APPEARANCE. 
(Plate XIII.) 
There is nothing in the external appearance of the corn to indicate 
the presence of a parasite in its tissues until about the time of flower- 
ing. Then it shows itself in the form of swellings of such a nature 
that the Germans call it ‘“‘boil smut.” These swellings vary in size 
from that of a pea to more than that of a man’s fist, and mark the 
lace where the spores are formed. With few exceptions all the 
<inds of smuts, over one hundred in number, form their spores in 
some definite place in the plant, most commonly in the floral organs. 
Corn Smut is the most marked exception to this, for it forms its spore 
masses in any part of the plant except the roots. 
*Fung. Car. Exs., IV, 100. 
+ Bot. Zeit., Vol. XXXTI, p. 122. 
¢ For fuller accounts of the history and literature of the smuts the reader is re- 
ferred to the works of Tulasne, Fischer de Waldheim, and Brefeld. 
