174 
to the surface. The fungus resembled Very closely members of the 
genus Gloeosporium. Farther investigation showed that older speci¬ 
mens possessed olive or dark-brown setae, intermingled with the color¬ 
less basidia. The setae are proportionately few where the substratum 
is soft, more numerous when it becomes hard or in the dead or nearly 
dried parts of the plant, particularly on the stems and the dissepiments 
of the open boll. The presence of setae shows the affinity of the fungus 
with the genus Colletotrichum. 
On the green bolls the fungus produces depressed spots, at first of a 
black color, caused by the death of the tissues. If the weather is favor¬ 
able for the development of numerous spores the dark depressions 
later assume a grayish or roseate tint from the lesser or greater mass 
of spores developed. Sometimes the depressions are not well marked, 
but the fungus being evenly distributed gives a black color to a large 
portion of the surface of the boll. A severe attack seems to hasten a 
premature partial opening of the boll, but frequently this checks the 
growth and the lint can not escape. In such cases the fungus fre¬ 
quently grows also on the lint. Besides these characteristic effects on 
the boll, the fungus severely injures other parts of the plant. It is a 
very common accompaniment of Cercospora gossypina , Cooke, and other 
fungi of “ black rust” on the leaves, and does much to aggravate that 
disease. So early as August 12 I found it upon the leaves, and it 
probably occurred earlier. 
The Colletotrichum also occasions a very distinct and destructive 
disease of the cotton plant. A remarkable example of this occurred on 
the Station farm in some cotton planted in “checks,” i. e., in hills with 
the rows running both ways. The portion of the field attacked was 
about 2 or 3 acres in extent. During August I noted on my weekly 
visits that the usual fungi of “black rust ” and “ red rust” were present, 
but not sufficient in extent to do any appreciable injury nor to character¬ 
ize these diseases as they are known to the farmers of Alabama. I 
found also the Colletotrichum principally on the edges of the leaves. 
In September the Colletotrichum severely attacked the stems of the 
upper part of the plant. The leaves soon appeared, as some expressed 
it, as if they were affected with a “ scald,” changing to various shades 
of yellowish or leaden green color. They soon withered and dried much 
as if killed by frost, presenting a decidedly different appearance from 
leaves killed by black rust. The stems became blackened and the death 
of the plant usually followed. 
I have observed the same characteristic disease in several localities 
around Auburn, but this patch of 2 or 3 acres is the largest I have met 
with. It is not improbable that in some of the cases reported as “ black 
rust,” where in the first stages of the disease it sweeps rapidly and sud¬ 
denly over certain spots, the Colletotrichum is the ultimate factor in 
causing the death of the plant, and then frequently continues the 
disease upon the bolls. 
