366 
Journal of Agricultural Research 
Vol. V, No. 9 
that the fungus found on the apricot was a species (S. laxa) distinct from 
that found on plums and cherries (S. cinerea). They also concluded that 
the American species must be 5 . 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 
S, cinerea more than 5 . fructigena . 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. 1 2 
An important taxonomic fact was brought out by Ewert (1912) when 
he showed that the Monilia spores of 5 . fructigena would not live over the 
winter, while those of 5 . cinerea would. This difference was not due to 
the effects of cold, as the spores of 5 . 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. 3 
The perfect stage of the cherry brown-rot fungus in Europe was not 
found until 1912. Westerdijk (1912) 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 5 . fructigena and S. cinerea sent to him from Europe. He concluded 
that the Monilia 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 S. cinerea. 
Conel (1914) made a study of the brown-rot in the vicinity of Champaign 
and Urbana, Ill., 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. 
2 Jehle also germinated spores found on mummies in the early spring. 
