430 
Journal of Agricultural Research 
Vol. VIII, No. ii 
All cultures were kept in the laboratory at room temperature, 12 0 to 
26° C., and in diffused daylight, so that they were subjected alike to 
Uny change of environmental conditions. 
In all cases 10 cultures of a species were made on each medium. Differ¬ 
ent forms of fructification which normally appear on a certain medium 
may not do so in every tube. For example, in a species where sporo- 
dochia are not abundant, they may perhaps form on only 2 or 3 of the 
10 stem plugs; or if the form produces green sclerotia, they may develop 
on not more than 5 of the 10 potato plugs. In some instances as many 
as 8 to 10 sets of 10 tubes each of a particular species were made. 
In making the microscopical examination note was taken of the size, 
abundance, and type of conidia (fig. 1, A-G), chlamydospores, and 
conidiophores. In measuring spores several fields were first examined 
to fix in mind the prevailing type and an average of 10 or more of these 
typical spores was made. Careful note was taken also of extreme types. 
In the macroscopic study of the cultures the nature of the stromata, 
the pionnotes and sporodochia, the character of the aerial mycelium, 
the color of spore masses, aerial and submerged mycelium and sub¬ 
stratum, and the production of sclerotia were considered. 
RESULTS OF THE COMPARISON OF THE SOYBEAN FUNGUS WITH OTHER 
MEMBERS OF THE SECTION ELEGANS 
• 
The first sets of parallel cultures were intended to serve in the separa¬ 
tion of any or all of the species of Fusarium causing wilt from the soy¬ 
bean fungus. F. discolor var. sulphureum, F. oxysporum , F. vasinfectum , 
F. lycopersici, F. niveum, F. tracheiphilum, and Fusarium sp. from 
soybean were therefore grown on the following media, several sets of 10 
cultures of each species being used on each medium: Potato plugs, 
steamed rice, cotton stems, potato hard agar, and string-bean hard 
agar. The cultures were examined when 8, 15, 19, 30, and 50 days old. 
The results are noted in Table I. Only those characters are recorded 
that are necessary or useful for the separation of the species. 
Table I.- —Characters which separate a number of the wilt-producing species of Fusarium 
from F. tracheiphilum and the soybean fungus 
Species. 
Sclerotia. 
Sporodochia. 
Pionnotes. 
Chlamydospores. 
F. discolor . 
None. 
Numerous.. 
.... .do. 
Perfect.... 
.do.... 
Intercalary; no measure¬ 
ments.. 
Intercalary and terminal; 
no measurements. 
Intercalary and termi¬ 
nal; 6 to 12 fx. 
Intercalary and termi¬ 
nal; no measurements. 
Same as for F. lycopersici. 
Intercalary and termi¬ 
nal; 6 tO 12 JU- 
Same as for F. tracked 
philum • 
F. vasinfectum . 
Green and flesh-col¬ 
ored. 
F. oxysporum . 
Few. 
Reduced.. 
Perfect.... 
Reduced.. 
None. 
F. lycopersici . 
Flesh-colored. 
Numerous... 
.do. 
F , niveum . 
Large green. 
F. tracheiphilum . 
Green and flesh-col¬ 
ored. 
Mostly green; some 
flesh-colored. 
Few. 
Fusarium sp. on soybean... 
.do. 
.do.. .. 
