38 
The dry weather also almost wholly prevented the fruiting of the 
fungus. Out of many hundred stems examined for spore tufts, during 
a period of 3 weeks following blossoming, I found only half a dozen. 
However, a microscopic examination showed the presence of mycelial 
threads in the tissues, and upon placing freshly gathered twigs in 
moist air for 12 hours many of them sent out the characteristic spore 
tufts of Monilia fructigena. By continuing this treatment another 12 
hours spore tufts pushed through the unbroken bark on about 75 per 
cent of the stems. This experiment was repeated some days later 
with similar results, but a third experiment, using twigs which had 
been picked 4 or 5 days and were somewhat dry, gave only 2 per cent 
with Monilia tufts at the end of 24 hours. Plate y, Fig. 3, gives an 
enlarged view of a twig bearing fruiting tufts after 12 hours in moist 
air. Fig. 4 shows a conidiophore and conidia from the same. 
The extrusion of gum from the vicinity of the blighted flowers was 
quite common (Plate v, Figs. 1 g and 2 g). On cutting through the bark 
of such twigs the vicinity of the cambium cylinder was invariably 
gummy, but this was less noticeable on dry twigs. 
Carefully made cross sections of freshly blighted twigs were sub¬ 
mitted to microscopic examination. The cambium and soft bast cylin¬ 
ders had disappeared almost completely with the formation of extensive 
gum pockets (Plate vi, Fig. 1). These pockets were full of the active 
mycelium of Monilia. This also penetrated into the cortical parenchyma 
to some extent, and to a lesser degree into the xylem. Practically 
speaking, the wood and pith and all of the cylinders external to the 
soft bast were intact. On unmagnified cross sections a zone of dis¬ 
coloration was visible between the wood and the bark. On magnifica¬ 
tion this was found to consist, as shown in Plate vi, Fig. 1, of a gum 
cavity containing mycelium and fragments of tissue and bordered by 
irregular dark zones, the one within composed of young wood and 
vessels laid down this spring, and the one without composed of rem¬ 
nants of soft bast and phloem rays. The bundles of bast fibers were 
also changed from a glistening white to a dirty yellowish brown. Plate 
Y, Figs. 5, 6, and 7, show mycelial threads from these cavities. It 
was easy to find threads overlying and interwoven with tissue. Plate 
Vi, Fig. 2 represents the appearance of the destroyed tissues on a 
normal cross section ; fig. 3 represents the same on a longitudinal radial 
section. 
