ASCOMYCETES 



197 



more at length, may begin and develop in various ways when 

 Botrytis is the cause, but it is finally known by the complete 

 collapse of the lettuce heads due to the death of the stem and leaf 

 bases. The conidial stage is also associated with various damping-off 

 diseases, and it is believed by Smith to" be the organism studied by 

 Marshall Ward as the cause of an important lily disease. 1 In all 

 cases the conidial stage of the fungus may develop abundantly 

 upon the dead parts, and it has the appearance of a gray mold. 



FIG. 74. BOTRYTIS CINEREA. (After R. E. Smith) 

 a, portion of conidiophore ; t>, organ of attachment 



The fungus : morphology and biology. Under Sclerotinin 

 Fnckeliana it is intended to include the forms of disease which 

 may be attributed in Europe to Botrytis cinerea Pers. and in 

 America to Botrytis vulgaris Fr. It has been satisfactorily dem- 

 onstrated that these two names apply to a single species, a typical 

 conidiophore of which is illustrated in Fig. 74. The observations 

 of De Bary first connected this conidial stage with an apothecial 

 form, Sclerotiiiia 1'uckcliana, produced from sclerotia of the Bo- 

 trytis on grape. Subsequently doubt arose regarding this Conner 

 tion, since many observers failed repeatedly to secure under any 



1 Ward, II. Marshall. Ann. Hot. 2 : 319-382. pis. 20-24. 



