Apr. as. 19*3 Species of Filsarium Isolated from Potato Tubers 
341 
various conditions which might influence the number of septations is 
discussed, and the results of actual investigations are recorded in detail. 
In summarizing the taxonomic portion of the paper the authors 
endeavor to find a logical place for their species, and after several sug¬ 
gestions and comparisons they leave it unplaced, but give a detailed 
description of the organism. Some pathological studies are discussed 
with emphasis on the mode of infection, resistance, and susceptibility 
of varieties and methods of control. 
Wollenweber {21), studying the genus Fusarium taxonomically, came 
to a few definite conclusions: The stroma as a taxonomic character in 
species determination is unreliable. A pure cultme method which gives 
the normal stages is necessary, and the culture media recommended was 
steamed stems of trees, shrubs, or herbaceous plants for conidia and 
chlamydospore production and rice, potato tubers, and other starchy 
media for secondary characters, such as color, extra large sclerotia, and 
stromata. He is not sure that Fusarium is an obligiate conidial stage 
of an ascomycete. He puts much emphasis on the importance of the 
proof of pathogenicity of the organisms, and in his discussions of each 
species he indicates the kind of parasite. 
Wollenweber was the first to assemble into sections species of Fusarium 
having related characters. He considered a uniform shape of conidia the 
most important of the characters on which the division could be based. 
The sections which he described in this paper have been used in all taxo¬ 
nomic work with this genus since that time. Other sections, of course, 
have been added, but the original sections have for the most part never 
needed to be amended. 
The 20 species of Fusarium described, of which only 3 are new, are 
grouped under the sections, practically all of which include wound para¬ 
sites capable of destroying parenchymatous tissue, except the first, which 
includes vascular parasites only. Wollenweber’s sections in their order 
are: Elegans, Martiella, Discolor, Gibbosum, Roseum, and Ventricosum. 
Later Wollenweber (22), in morphological and‘pathological study of 
the divisions of fungi having cylindrical and crescent-shaped conidia, 
states definitely that fungi with cylindrical septate conidia fall outside 
the genus Fusarium, and belong, when the perfect form is known, to the 
genera Nectria, Hypomyces, and Mycosphaerella, and, when the perfect 
form is not known, to Cylindrocarpon when chlamydospores are absent 
and to Ramularia when they are present. 
Lewis (ij), working in Maine, carried on comparative studies with some 
40 different cultures of Fusarium isolated from various hosts, including 
7 isolated from potatoes. He noted how the growth of the cultures was 
effected by different media, different quantities of acid and alkali, and 
different temperatures. He tested for gas in fermentation tubes, but 
obtained negative results only. Tests of pathogenicity were carried on 
with all of the cultures, and considerable cross inoculation work was done. 
He made no attempt to identify the species, because the published de¬ 
scriptions were so incomplete as to make critical comparisons with them 
impossible. However, Wollenweber was in the United States at that 
time, and Lewis sent his cultures to Wollenweber, who identified most of 
them. His results were added as an appendix to the bulletin. 
Four of these species —Fusarium poae^ F. helianth% F. conglutinans ^ 
and F. pirium —do not later appear in the literature as occurring on 
potato. Sherbakoff {18) says of the first two that they are closely 
