538 
Journal of Agricultural Research 
Vol. XXXI, No. 6 
remained uninfected, indicates that this organ is immune to infection, 
probably because of its lack of stomata. But the curved hypo- 
cotyl emerging from the same opening in the end of the seed coat 
drags after it the two cotyledons which must slide through in direct 
contact with the infected tissue, thus exposing them to spore con¬ 
tamination (pi. 5, C). 
When wetted, the spore chains on the sporophores break up at 
once, the spores being readily dispersed in a film of water such as is 
very likely to be continuous from the seed coat to the emerging 
cotyledons, at least at some time during their emergence. Exami¬ 
nation of an empty seed coat showed that the fungus was sporulating 
along both edges of the opening through which the cotyledons had 
emerged. 
Since in the tests just noted the seedlings could not be grown in 
the damp chambers long enough to Obtain evidence of infection, 
similar plantings were made, February 7, in pots of steamed sand 
placed m an inclosed compartment in a greenhouse in which the 
disease had never been present. These pots were watered with 
such care that there was practically no spattering. Not very many 
of these seedlings carried the seed coats up into the air. An exami¬ 
nation made after 29 days revealed no infection, but 10 days after 
that 2 seedlings, each of which bore an infected cotyledon, were 
found (pi. 5, C). One of these was among the 9 seedlings grown 
from seeds with infected hila, and 1 among the 40 seedlings grown 
from seeds bearing adherent fragments of the infected fruit tissue. 
These seeds had been dried one month before planting. In these 
cases of primary infection there was abundant sporulation of the 
E arasite on both surfaces of the infected cotyledon, more abundant 
owever, on the lower. From such primary infections, the spores 
might readily be spread by air and water to other plants in the 
plant bed. Thus the disease might establish itself in a crop by pri¬ 
mary infection of the cotyledons from either infected or contaminated 
seeds. 
It seems then that the disease may be transmitted by infected 
or surface-contaminated seed as a result of the sporulation of the 
fungus on the infected tissues. If there is any fruit infection in the 
fields from which commercial seed is saved, the disease may be 
widely disseminated through such seed. The disease occurs only 
to a slight extent in the field crop in Indiana; it seems to be more 
prevalent as a field disease in more humid regions. It has been 
reported as a serious field disease near Norfolk, Va., by Smith and 
Zimmerley (14 ); and it has been reported from South Carolina ; and*, 
according to the reports of the Federal plant disease survey, it has 
occurred as a field disease in Florida, Louisiana, Virginia, Kentucky, 
and Ohio. It would seem possible, therefore, that fruit infection 
may occur in seed fields. Greenhouse growers who are saving seed 
should guard against the selection of iniected fruits. 
SUMMARY 
A conspicuous, black, stem-end rot of both immature and ripe 
S eenhouse tomatoes has been found to be caused by the leaf-mold 
ngus, Cladosporium fulvum Cke. 
This fungus also causes blackened radial furrows in the fruit, and 
- lopsided fruits which tend to remain green or yell ow on the retarded side. 
