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Journal of Agricultural Research 



Vol. XX, No. 4 



be filled with white wefts of mycelium, which in a few days are replaced 

 by numerous small black sclerotia. General observations indicate that 

 the fungus possibly causes a rather more rapid decay and collapse of 

 plants than is caused by S. libertiana. The wefts of white mycelium in 

 decaying plants are less conspicuous, and the sclerotia are much smaller 

 and much more numerous than in plants attacked by 5. libertiana. 



On several occasions bits of culture media covered with mycelium of 

 the fungus have been placed on growing lettuce plants. When moist 

 conditions have followed the inoculation, characteristic rapid decay has 

 invariably resulted. Prof. H. H. Whetzel has found that the fungus is 

 capable of attacking a large number of plants, data on which will be 



Fig. i. — Camera lucida drawings of S. m,inor: A, microconidia and conodiophores; B, ascospores; C, 

 germinating ascospores; D, asci and paraphyses. 



published in connection with his studies of the genera Sclerotinia and 

 Botrytis. 



Strains of the fungus isolated from lettuce grown in the vicinity of 

 New York, Rochester, and South Lima, N. Y., Philadelphia, Pa., and 

 Sanford, Fla., have been grown in parallel cultures on various media 

 and have in every case appeared to be identical. Apothecia produced 

 by the three strains from New York State have shown neither macro- 

 scopic nor microscopic differences. 



Apothecia (PI. 59, B, C) have several times developed from sclerotia 

 which had been allowed to age on unsterilized sand for from 4 to 12 

 months and which were then held under moist and well-lighted condi- 

 tions. Studies of fresh mature apothecia were made in 191 2, 191 4, and 

 1917 (fig. 1). Measurements of spores, asci, and paraphyses in the 



