264 
Journal of Agricultural Research 
Vol. II, No. 4 
furcate. The fungus is ochreous to salmon colored in light, in darkness it fades to 
brownish white. Thalloplectenchymata wine red in the acid modification (on rice) 
and blue spotted in the basic modification (on potato tubers); but sclerotial plec- 
tenchymata entirely wanting. Chlamydospores intercalated, globose to ovoid, 
i-celled forms averaging 7 to 10 p, 2-celled forms more rare but with a somewhat larger 
major axis. 
Habitat.—A cosmopolitan species. Inhabits the root system of such plants as 
Allium, Brassica, Ipomoea, Solanum, Capsicum, Apium, Citrullus. This species is 
especially abundant in North America. Probable cause of jelly end-rot of potato 
tubers and root troubles. 
In Europe this fungus is confined to the cooler part of the Temperate 
Zone. In Germany and Norway it is common on the tuber, the stolon, 
and other parts of the root system of Solanum tuberosum. In America 
at least 20 strains of this fungus from potato have been added to the 
writer’s collections, which were mostly transferred to him in pure culture 
for determination. The following States may be recorded as sources of 
this material: Tennessee, New York, Vermont, Maine, Ohio, Illinois, 
Iowa, Wisconsin, Minnesota, Washington, Oregon, California, and the 
District of Columbia. Furthermore, Fusarium orthoceras was sent with 
potatoes from Cape Colony, Africa, and from Chiloe, South America, also 
from Great Britain. These additional isolations proved its cosmopoli¬ 
tan nature. In the Bureau of Plant Industry, Washington, D. C., the 
fungus was frequently isolated and determined from diseased plants, 
such as onion, cabbage, sweet potato, celery, and occasionally from 
watermelon (Citrullus) and sweet pepper (Capsicum). The determina¬ 
tion of this species is somewhat handicapped by the predomination of 
unicellular conidia, but repeated transfers and variation of media are 
sufficient means to provide sickle-shaped septate spores of typical form. 
The conidia and the chlamydospores, the mycelium with its jellied 
growth in old cultures, and its deep wine-red to purple-acid modification 
(turning blue with alkali) on rice allowed the final determinations 
Only a few, not exceeding 15 per cent, of the conidia are 3-septate, as 
indicated in the diagnosis of the type strain studied in Berlin. This 
low percentage of the characteristic sickle-shaped conidia was quite 
uniformly found in many strains from the same or from different host 
plants. However, one strain out of several isolated from Ipomoea batatas 
had as many as 100 per cent of 3-septate conidia (PI. XVI, fig. N) under 
the same conditions, where the other strains had but a few per cent of 
them. 
7. Fusarium orthoceras, var. triseptatum, n. var. 
Diagnosis.—Differs from Fusarium orthoceras in having a higher septation of conidia, 
by the presence of sporodochia, and a reduced pionnotes. Under normal conditions 
as many as xoo per cent of the conidia are 3-septate. Ten per cent of 4- and 5-septate 
conidia are found. Unicellular conidia and chlamydospores occur and prevail under 
certain conditions. 
Habitat.—On partly decayed roots of Ipomoea batatas , Newark, Del. (collected by 
Taubenhaus, 1912). 
