1922] WILLAMAN & SANDSTROM—SCLEROTINIA 2905 
the surface of the fruits to become brown was recorded, as shown 
in table IJ. These figures show the same slower rate of rotting of 
the resistant varieties. 
TABLE II 
BEHAVIOR OF VARIOUS PLUM VARIETIES TOWARD ROTTING ORGANISM AT 
STAGE OF GROWTH 
RELATIVE ABUNDANCE ON 
D J : SURFACE 
: FOR SURFACE. | DAYS REQUIRED | OF 
ARIETIES 
gh nett iy ROTTING : 
Hyphae Spores 
Resistant 
Burbank X Wolf 9........ 13 15 fort “ts 
Burbank X Wolf 16....... 7 13 ee Se =F 
Abundance X Wolf 30... . 6 13 + 9 A Sa 
Susceptib 
Cass to oe 5 9 +44 +++ 
Sand Cherry X Formosa.. 5 10 +++ +++ 
Fic. x 
Fic, .2 
Fic —Fig. 1, dish of Burbank X Wolf 16 plums at end of rotting period in 
half-grown fe of growth (table II), showing abundance of hyphae on surface and 
relative scarcity of spore tufts; fig. 2, dish of Abundance Wolf 30 plums at end 
of rotting period in halbaviies stage of —_ (table II), showing abundance of 
echt and scarcity of hyphae on surface 
Another varietal difference was the character of the aerial 
portions of the fungus, especially as to the relative abundance of 
spore tufts and of hyphae. These data are recorded in table II. 
Although the differences among the varieties were well marked, 
they are not correlated in any striking way with resistance 
