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in its ordinary form was not the cause of a large part of the trouble 

 known to the growers as Drop. Yet we still regarded the disease 

 as being caused by a peculiar form of this fungus and have so 

 alluded to it in our annual reports from year to year. The most 

 prominent difference was that in many cases of the disease the gray, 

 dusty growth of Botrytis spores did not appear. A mould was 

 abundant in and upon affected plants, but it was white in color and 

 bore no spores whatever, being simply a delicate, cottony mass of 

 fungous filaments. To the practical lettuce grower there is no 

 great importance in the simple fact itself whether one fungus or 

 another causes the rotting which carries off his crop. But in this 

 case, when remedies come to be considered, the question is of fund- 

 amental importance. Botrytis spreads in the house and lives from 

 season to season and crop to crop by means of its spores which 

 float in the air. Further it is known that this fungus can usually be 

 kept down by skillful handling of the crop. If, therefore, anything 

 else. is concerned in the trouble which may propagate differently and 

 perhaps differ entirely in its relation to the lettuce plant, it is of the 

 greatest practical importance to know just what we are dealing 

 with ; its habits, life history, course of development, and relation to 

 the crop. Without this knowledge we must work largely by chance 

 and in a very uncertain manner. We have therefore devoted much 

 attention to the clearing up of this point and feel that we can speak 

 with certainty in regard to it. It will not be necessary, however, to 

 discuss here the technical side of the subject further than' is neces- 

 sary to explain matters.* 



There is a fungus which attacks many different kinds of plants, 

 called Sderotinia Libertiana. It lives mostly in the soil, usually 

 attacking plants just at the surface of the ground, where the stem 

 rots off. It has long been a question whether or not Botrytis 

 vulgaris has any connection with this fungus, many believing it to 

 be a form of it. They are similar in their effect on plants as well as 

 in other ways and are often found together. Humphrey described 

 the disease of green-house cucumbers called " Timber Rot " as 

 caused by Sderotinia, and finding Botrytis in the same house argued 

 a connection between the two. This point we have carefully 

 studied and found that the two forms, though closely related to each 

 other, which accounts for their similarities, are nevertheless entirely 

 distinct species, one never producing the other. With regard to 



*The above mentioned article by one of the writers deals especially with tliis point. 



