X. C. Experiment Station 
13 
place of inoculations with each of the organisms. Lettuce plants, fur¬ 
thermore, became affected when diseased clover plants were transplanted 
beside them. These reciprocal inoculations leave no doubt that both 
clover and lettuce may be attacked by either S. trifoliorum or S. liberti- 
ana. Smith’s (21) observations on the cause of cottony rot of lemons 
are of interest in this connection since he states that their decay is due 
to S. libertiana, although S. trifoliorum is able to develop on artificially 
inoculated lemons and may cause some of the infection. He also points 
out that alfalfa and vetch when grown as cover crops in lemon groves 
are attacked by S. libertiana. The confusion which has existed in the 
literature dealing with the identity and relationship of S. trifoliorum 
and S. libertiana is, therefore, clarified by these reciprocal inoculations 
which are in part a confirmation of studies and observations by 
Smith (21). 
Means of Spread of Stem Rot 
It seems highly probable that stem rot of clover was introduced into 
America from Europe, but the method of its introduction, together with 
the means for its spread into new localities each year, have remained 
more or less problematical. Eriksson (6) states that the fungus undoubt¬ 
edly overwinters as hyphae adhering to the seeds and not as sclerotia or 
spores and that the disease is spread by this means. 
Coleman (4) suggests that sclerotia mixed with the seed are a prob¬ 
able means of the distribution, although spores adhering to the seeds are 
also a possible means. Observations on this point, first made during 
the fall of 1914, by Prof. H. R. Fulton, then Plant Pathologist for the 
Horth Carolina Experiment Station, show that sclerotia are present in 
commercial crimson clover seed. He states :* “I received from county 
agents some six or eight samples of seed. Two of these, I distinctly re¬ 
member, showed the contamination wdth sclerotia.” If seed were 
harvested from affected fields, sclerotia would almost certainly be mixed 
with seed (Plate 2, Fig. 3), and would remain with them even though the 
seed were very carefully cleaned. Seed contaminated with sclerotia are, 
therefore, believed to account for the introduction and presence of stem 
rot of clover. 
Humerous possibilities might be suggested to account for the local 
distribution of the disease. The fungus is known to spread through the 
soil along the margin of the diseased areas. Further, the sclerotia which 
normally remain dormant for a time, even though favorable conditions 
for their germination may obtain and which may retain vitality for at 
least two and one-half years under laboratory conditions and one and 
one-half years in the soil (18) may aid in its spread. They may be dis- 
*From a letter dated October 25, 1917. 
