366 Journal of Agricultural Research voI.v.no. 9 



that the fungus found on the apricot was a species (5. laxa) distinct from 

 that found on plums and cherries (S. cinerea). They also concluded that 

 the American species must be .S. cinerea. A comparison of the ascospores 

 of 5. cinerea with those of 5. fructigena brought out the fact that the for- 

 mer always contain from one to many oil globules, while the latter con- 

 tain none. 



Pollock (1909), in a study of the Michigan brown-rot fungus, concluded 

 that it was probably the same species which Norton described, and that, 

 so far as the chlamydospore measurements were concerned, it resembled 

 5. cinerea more than 5. frtictigena. Pollock also showed that the micro- 

 conidia observed by Woronin (1888) on certain other species of Sclero- 

 tinia and by Humphrey (1891) as appearing on plums which did not 

 produce spore tufts were also produced in abundance when ascospores 

 of the American brown-rot fungus were germinated in distilled water.^ 



An important taxonomic fact was brought out by Ewert (191 2) when 

 he showed that the Monilia spores of 5. fructigena would not live over the 

 winter, while those of S. cinerea would. This difference was not due to 

 the effects of cold, as the spores of S. fructigena would stand low tem- 

 peratures. That the spores of the American form would live over the 

 winter was shown by Arthur (1886), who on May 8 germinated spores 

 taken from mummies of cherries which had hung on the tree all winter. 

 Galloway (1889), in May, 1888, germinated spores taken from mummies 

 collected in July, 1886.2 



The perfect stage of the cherry brown-rot fungus in Europe was not 

 found until 191 2. Westerdijk (191 2) described it at this time and con- 

 cluded (p. 41), from ascus and ascospore measurements, that "Neben 

 den 3 beschriebenen Obstsclerotinien ist dann also eine spezielle Kirschen- 

 sclerotinie aufzustellen." The asci and ascospore measurements pre- 

 sented by Reade (1908) and Pollock (1909), however, do not warrant 

 this conclusion. 



Matheny (1913) made an extensive study of the brown-rot fungus from 

 various parts of this country and compared it closely with pure cultures 

 of S. fructigena and 5. cinerea sent to him from Europe. He concluded 

 that the MoniUa stage in this country agreed very closely with that of 

 5. cinerea of Europe and that the apothecial stage differed in shape of 

 spore and in the presence of oil globules in the ascospores from that of 

 5. fructigena and referred the American brown-rot fungus to 5. cinerea. 

 Conel (1914) made a study of the brown-rot in the vicinity of Champaign 

 and Urbana, 111., and decided, both because of its morphological char- 

 acters and from the fact that the Monilia form is capable of living over 

 winter, that the fungus was 5. cinerea. 



1 Jehle in an unpublished thesis on file at the University of Minnesota also observed the production of 

 these conidia from ascospores, and on the same hypha observed the Monilia spores, thereby definitely 

 connecting the perfect and the Monilia stages. 



* Jehle also germinated spores foimd on mimunies in the early spring. 



