[Vor. 8 
12 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
served since 1866. Shear (’07) states that the fungus is dis- 
tributed from eastern Texas to southern California, and that 
it has been found in southern Oklahoma and Indian Territory. 
The writer failed to find the organism in western Louisiana 
and southwestern Arkansas in 1901, but it was observed in 
southern Oklahoma in 1915. I am unaware of the data on 
which the occurrence of the fungus westward to California is 
reported. Nevertheless, considering the long period of time 
during which the Ozoniwm has been a serious disease-inducing 
factor in Texas, it is rather remarkable that it has not been 
found in Louisiana and Mississippi. In these states the cot- 
ton wilt fungus, Fusarium vasinfectum, is well known, but the 
Ozonium has never been reported, so far as can be learned. 
It is almost impossible to assume that the fungus has not 
been distributed to these states through the various possible 
commercial channels; so that one is impelled to draw the in- 
ference that the establishment of the fungus farther east- 
ward is limited by climatic or soil factors. 
It should be recalled that Pammel reported the disease 
common throughout all sections of Texas in which cotton was 
grown, with the exception of Ше gulf prairie region and cer- 
tain alluvial soils. It seems now certain that there 1s no soil 
type in the cotton-producing section of the state which is free 
from the disease. Nevertheless, the percentage of loss has 
been invariably greater in the black prairie or blaek waxy 
soils, whether with or without outeroppings of rotten lime- 
stone. As noted later, the organism occurs on a number of 
native plants, both trees and herbs, but the observations thus 
far made give no clue as to whether or not it may be eonsid- 
ered endemie. I have been unable to secure data on the oc- 
currence of this fungus from Mexico southward. 
From the reports of Pammel, Heald, Heald and Wolf, and 
from my own observations, the following host plants may be 
enumerated. 
Trees and shrubs: Ulmus americana, Broussonetia papy- 
rifera, Morus alba, Ficus Carica, Acer saccharinum, Tilia 
americana, Fraxinus americana, Diospyros Kaki, Melia Aze- 
darach, Pyrus communis, P. Malus, Cydonia vulgaris, Robinia 
Pseudo-Acacia, Prunus Persica, P. sp. (cherry), and Hibiscus 
syriacus. 
