September, 1955 FORSBERG: 
F. oxysporum Schlecht. var. gladioli Mas- 
sey as the cause of brown rot, and merely 
Fusarium sp. as the cause of basal dry rot. 
Gould (1949) called F. oxysporum f. 
gladioli the cause of Fusarium rot. Miller 
& Magie (1950) listed F. oxysporum f. 
gladioli as the cause of Fusarium storage 
rot of gladiolus corms. Magie (1950) re- 
ferred to the causal agent of Fusarium yel- 
lows and Fusarium corm rot as IF. oxy- 
sporum f. gladiolli. 
Bald (1953) stated, “Typical single 
spore cultures from basal rot, yellows, and 
intermediate infections were submitted to 
Dr. W. C. Snyder for identification. He 
placed all the cultures in the species Fu- 
sarium oxysporum Schl. As these Fusaria 
were obtained from active lesions, and 
some similar isolates were shown by inocu- 
lation tests to be pathogenic on gladiolus 
corms, the strains causing basal rot, yel- 
lows, and intermediate symptoms on glad- 
ioli in southern California have been pro- 
visionally grouped under the name F. oxy- 
sporum f. gladioli (Massey) Sny. and 
Hans.” 
Difficulties in Classifying Fusaria 
A review of the literature indicates that 
the difficulties encountered by plant pathol- 
ogists in classifying strains of the gladiolus 
Fusarium have been great and are similar 
to the experiences of many other workers 
faced with the task of determining the re- 
lationship and specific name to be applied 
to a pathogenic Fusarium. 
Some of the confusion is a result of the 
use of two different systems of nomencla- 
ture and taxonomy now available for nam- 
ing and classifying isolates of Fusarium. 
These are the detailed system of Wollen- 
weber & Reinking (1935) and the simpli- 
fied system of Snyder & Hansen (1940, 
1941, 1945). 
In the system of Wollenweber & Rein- 
king (1935), the genus Fusarium is di- 
vided into 16 named sections in which a 
total of 65 species, 55 varieties, and 22 
forms are differentiated. This system is 
based largely on recommendations made at 
a conference held in Madison, Wisconsin, 
in 1924 (Wollenweber ef al. 1925). Ac- 
cording to these recommendations, species 
and varieties must be distinguished by 
FusArRIUM DISEASE OF GLADIOLUS 453 
morphological characters only. Each spe- 
cies includes groups of individuals that can 
be distinguished by morphological charac- 
ters which must be “of such a nature as to 
be applicable and usable by mycologists in 
general and which will be most serviceable 
for practical purposes.” Each variety is 
distinguished by morphological characters 
of eS importance than those used for spe- 
cific segregation. Groups of individuals 
differing from the species and the variety 
only in certain physiological characters are 
separated as forms. This system failed to 
meet with unqualified approval because of 
difficulties that still were encountered by 
workers in attempting to classify specific 
isolates of Fusarium. 
The simplified system of nomenclature 
and taxonomy proposed by Snyder & Han- 
sen (1940, 1941, 1945) was based on their 
extensive investigations of the variability 
shown in culture by species, varieties, and 
forms of Fusarium. Section Bleoae was 
the first to be revised according to their 
concept of species. Simplification was 
achieved by emending the description of 
one species, Fusarium oxysporum Schl., to 
agree with the description of section Ele- 
gans given by Wollenweber (1913). The 
10 species, 18 varieties, and 12 forms com- 
prising section Elegans of Wollenweber & 
Reinking (1935) were placed in one spe- 
cies, Fusarium oxysporum, on the sole 
basis of morphology. ‘Twenty-five para- 
sites of the section were made forms of this 
common species on the basis of pathoge- 
nicity alone. Revision of the other sec- 
tions followed. As a result of the complete 
revision of the genus, the 16 sections, 65 
species, 55 varieties, and 22 forms of Fu- 
sarium of Wollenweber & Reinking were 
reduced to 8 species and 34 forms. No va- 
rieties were recognized in the system of 
Snvder & Hansen. 
Massey (1926), McCulloch (1944), 
and Nelson (1948) used the system of 
Wollenweber & Reinking to designate spe- 
cies names for the gladiolus Fusarium. 
Gould (1949), Miller & Magie (1950), 
Magie (1950), and Bald (1953) used the 
system of Snyder & Hansen. McClellan 
(1945, 1947, 1948) used both systems. 
Wollenweber’s classification was the only 
one in existence at the time Massey pub- 
lished the results of his investigations. 
