374 Journal of Agricultural Research voi. v, no. 9 



By comparing the figures given by Westerdijk (191 2) for the cherry 

 fungus with those given above, it will be seen that they fall well within 

 the range of 5. cinerea, and as this difference in the size of the asci and 

 of the ascospbres was the only one upon which she based her conclusion 

 as to its being a separate form, it seems safe to conclude that what she 

 described was the perfect stage of 5. cinerea. 



It has already been pointed out that the Monilia stage of the apricot 

 fungus, described by Aderhold and Ruhland (1905), compares favorably 

 with the Monilia stage of the American brown-rot fungus, and they 

 showed that it was identical, except for slight differences in chlamy do- 

 spore size, with that of the European 5. cinerea. By referring to Table 

 II it will be seen that the ascus and ascospore measurements given for 

 the perfect stage of 5. laxa fall well within the limits determined for 

 5. cinerea. Considering the fact that at present there are no known 

 morphological differences between 5. cinerea and the apricot fungus, is 

 the fact that Aderhold and Ruhland were able to get infection of plum 

 flowers in only a few cases with chlamydospores of 5. iaxa sufficient evi- 

 dence to make this a separate species ? 



MICROCONIDIAL STAGE 



The microconidial stage, as was stated above, has been described by 

 Woronin for a number of species of Sclerotinia, including 5. fructigena and 

 5. cinerea. He, however, could show no differences between the spores of 

 the two latter species, and they are therefore of little value in identifica- 

 tion of the species. 



The production of the microcondia was first seen by the writer in a 

 potato-plug culture of the local fungus nearly a year old. The spores 

 ranged from 2.2 to 2.6ju in diameter, were spherical, and contained a large 

 refractive globule. They were later found on agar cultures in great 

 abundance, in hanging drops of distilled water, and also in hanging drops 

 of I per cent malic, 0.062 gallic, 0.062 and 0.25 per cent tannic acids. In 

 the latter cases the flask-shaped sterigmata could be seen. Chains of 

 from 15 to 20 spores were not uncommon. They were also produced in 

 great abundance on the surface of a very young Surprise plum picked and 

 inoculated June 3. These spores ranged in size from 2.55/x to 3.22/i, aver- 

 aging for 25 measurements 2.72/i. The microconidia produced in the 

 I per cent malic-acid solution were larger, ranging from 2.60 to 3.79M. 

 measurements of 25 spores averaging 3.14^- 



PHYSIOLOGICAL AND PATHOLOGICAL RELATIONS 



INFECTION 



Opinions differ as to the ability of the brown-rot fungus to penetrate 

 the uninjured surface of fruits. Peck (1881) was unable to get infection 

 of fruits when the spores were planted on the uninjured surface. Smith 



