A scigerous Stage of a ‘ Brown Rot ' Fungus. 1 3 1 
. ( 
It has been shown (10) that the average size of the conidia of Monilia 
cinerea when growing on fruit in summer is about 17XII/X, and it will 
be seen that the above dimensions for the conidia of the ascosporic strain 
produced under similar conditions are of the same order* 
(d) Inoculation of Apple Flowers. 
Apple flowers (variety James Grieve) were inoculated on the stigmas 
with conidia of the plum Sclerotinia , and simultaneously on the same tree 
others were inoculated with a strain of Monilia cinerea isolated from a dead 
flowering spur of an apple tree. For each strain eight inflorescences were 
selected and two flowers were inoculated on each inflorescence ; thus six- 
teen flowers were inoculated with the Sclerotinia strain and sixteen with the 
apple strain of Monilia. 
Of the eight inflorescences inoculated with the apple Monilia seven 
were killed outright, with all their flowers and leaves, the wilting of the 
leaves (which indicates that the fungus has extended from the infected 
flowers into the axis of the inflorescence) being noticeable in from twelve to 
seventeen days after inoculation of the stigmas. 
Of the eight inflorescences inoculated with the plum Sclerotinia strain 
the flowering axis was not invaded in any one instance, although the inocu- 
lated flowers themselves showed the early symptoms of infection by a brown- 
ing of the stigmas and styles when no such discoloration was observable 
on control flowers ; one of these inoculated flowers, however, developed into 
fruit, while the rest fell off. 
The results obtained from the inoculation experiments offer no evidence 
that the mode of parasitism of the fungus is modified in any way by the 
interpolation of the ascigerous stage, and confirm the conclusions given in 
a previous paper (10) that Monilia ( Sclerotinia ) cinerea is represented in 
Britain by two ‘ biologic forms \ one of which causes a 4 Blossom Wilt and 
Canker Disease ’ of apple -trees, whilst the other is unable to extend 
farther than the pedicel of the inoculated apple flower. From its mode of 
growth in cultures, its parasitic habit, and the morphology of its conidial 
stage when growing on plums and cherries, together with its inability to 
invade the flowering spurs of apple trees, the Sclerotinia found on plums is 
shown to be the ascigerous stage of Monilia cinerea forma pruni referred 
to in that paper. 
A Comparison of the Brown Rot Sclerotinias. 
The following table summarizes the results obtained with respect to 
dimensions of asci and ascospores of Brown Rot Sclerotinias as determined 
by various authors : 
K 2 
