12 
Research Bulletin No. 1 
by a few lines of description in which the name of the host played 
an important part. In 1910 appeared a publication entitled 
"Grundlagen einer Monographie der Gattung Fusarium (Link)/' 
by Appel and Wollenweber. In this the authors have laid the 
foundation for a systematic treatment of the genus upon mor- 
phological characters. 
During the fall of 1911 the morphological study of this organ- 
ism, previously shown to be responsible for the dry rot of the 
Irish potato tuber herein described, was undertaken along the 
lines laid down by Appel and Wollenweber.* 
The genus Fusarium was defined by Link in 1809. together 
with the allied genera, Fusidium, Fusisporium, and* A tract ium. 
From time to time Link dropped one or the other or combined 
them in various ways. In one of his late works in 1824 he de 
fines the genera Fusisporium, Fusidium, and Fusarium, using 
the presence or absence of a thallus as prime character. As it 
happened the genera were thereby also divided on the basis of 
seDtation of spores, Fusisporium having non-septate spores, 
Fusidium and Fusarium septate spores. 
In 1824 Schlechtendahl introduced the use of the curvature of 
the spores as a character, which was also used by Corda in 1829. 
The latter distinguished Fusarium as having only curved spores 
and Fusidium as having both curved and straight spores. Later, 
1837, he changed his views somewhat, giving Fusidium only 
straight spores, and Fusarium curved and straight spores, and 
dropped all forms which had pluri-septate conidia from these 
genera and used them to establish the genera Fusoma and 
Helenosporium. putting them under his Phragmidiaceae, while 
he puts his Fusidium and Fusarium under the Caeomaceae, and 
Fusisporium under the Sporotrichaceae. 
Fries in 1845 reduced all these forms to two genera, Fusarium 
(Link) and Fusisporium (Link), but grouped certain organisms 
producing sickle-shaped spores in slimy layers into one genus 
which he called Pionnotes. 
Saccardo in 1886 divided the genus Fusarium into the fol- 
lowing subgenera, Eu-Fusarium, Fusamen, and Leptosporium 
Eu-Fusarium was described as having cylindrical, spindle and 
sickle-shaped conidia with one or more septa, and was subdivided 
into Selenosporium (Corda) and Fusisporium (Link). Fusamen 
has similar conidia which are not septate, however, and Lepto- 
sporium has shorter, ovate or somewhat elongated non-septate 
conidia. Fusamen was divided into Selenospora and Fusispora. 
* An account of the morphology of the causal organism was sub- 
mitted as part of a thesis for the M. A. degree from the University of 
Nebraska in May, 1912, bv G. K. K. Link. 
