[Vor. 3 
32 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
rounded ends, long axis slightly bent, dimensions 4 X 19u. 
Three-septate conidia fusiform, hyaline, with both end-cells 
tapering and with rounded tips, no sharply differentiated foot, 
dimensions 3.5-5.5 X 25-334. Conidia with higher septation 
very rare. 
In culture aérial mycelium white at first, becoming cream- 
colored and finally showing a development of ochreous strands 
of thallo-plectenchymatic tissue throughout, but no sclerotia. 
Grows well on potato agar, dextrose bouillon agar, Uschinsky’s 
fluid, cooked rice, cooked potato plugs, and potato stems. On 
no medium is there any color production except the slight 
yellowing spoken of above. In older cultures terminal or in- 
tercalary chlamydospores are produced. They are usually one-, 
sometimes two-celled, spherical to ovoid with a thick irregular 
wall, frequently slightly colored. Dimensions 7-12 X 7-15». 
The fungus is found in the soil and is a vascular parasite 
attacking cabbage, Brassica oleracea var. capitata, causing the 
yellows, or wilt disease. It has also been isolated as a sapro- 
phyte from China aster and tubers of potato (Lewis, '13).' 
TEMPERATURE STUDIES 
Tn view of the later work in regard to the relation of temper- 
ature to the occurrence of the disease, it will be well to dis- 
cuss briefly this relation for the fungus in pure culture, both 
as to growth and germination of conidia. The latter will be 
considered first. 
In order to obtain spores of the fungus free from pieces of 
mycelium, a bit of mycelium was placed in a hanging-drop of 
Uschinsky’s fluid in a Van Tieghem cell which was partially 
filled with Uschinsky’s fluid below. The spores were formed 
abundantly at room temperatures in forty-eight hours and al- 
lowed to drop into the lower liquid from which they were 
1 Through the kindness of Dr. W. J. Morse, of the Maine Agricultural Expe- 
ent Station, ior ore rs of these two strains of Fusarium conglutinans Wes? 
obtained, and in ations made on February 2, 1915, on five plants each, 
again on Ke 26, 1915, with а strain from aster on ten plants; both 
gave negative results. This would indicate Ser they Geste to a saprophytic 
strain, although the results might be due to the fact that the — ad bee 
so long in eulture that they ha d lost their гр or to the small number of 
trials made. Control cultures of this fungus from ca abbage, however gave 80 per 
cent infeetion in the first case and 100 per cent in the second tria 
