370 
Journal of Agricultural Research 
Vol. V, No. 9 
Gold is a thin-skinned susceptible variety. Sultan is not known to the 
writer. 
The three varieties designated “S. D. Nos. 1,2, and 3” are varieties 
obtained from Mr. A. Brackett, of Excelsior, who received them from the 
South Dakota Experiment Station. Their true names were not known 
to Mr. Brackett. S. D. No. 1 is a thin-skinned variety and rotted badly 
on the trees when sprayed once with Bordeaux mixture. S. D. Nos. 2 
and 3 were thicker skinned, firmer varieties and did not rot after one 
spraying, many fruits drying on the trees. All appear to be sand-cherry 
hybrids. 
Compass, a hybrid between a sand cherry and P. americana (Hansen, 
1911), is a thin-skinned variety which becomes soft on ripening and is 
susceptible to the brown-rot. Reagan, a hybrid of Wayland (P. horiu- 
lana) X P. americana (Hedrick, 1911) is thick-skinned, very firm when 
ripe, and is very resistant to the rot. Specimens of the ripe fruit used 
were received from the New York Experiment Station, Geneva, N. Y. 
Ocheeda and Harrison are varieties of P. americana . Manitoba No. 1 
is probably a variety of P. nigra . Hammer is a hybrid between P. hor~ 
tulana mineri and P. americana (Hedrick, 1911). These varieties were 
obtained from the orchard at University Farm. 
TAXONOMY OF THE FUNGUS 
MONILIA STAGE 
The brown-rot fungus in Minnesota is found for the most part affecting 
plums, but to a very limited extent also attacking the apple. It appears 
on the plum first as a small brown or purple spot, which increases very 
rapidly in size. In a very short time the spore tufts appear irregularly 
over the surface of the rotted area. These are usually small and ashen 
gray in color, although in many cases the color varies to a yellow ocher. 
Plums inoculated through a wound made by cutting off the tip of the 
fruit, when allowed to rot under a cardboard box in nearly total darkness, 
produced spores of a bright-ocher color over the wounded area and in 
some cases through the skin. Mummies collected from trees in the late 
fall showed spore tufts which varied from gray to a light ocher. The 
chlamydospores of the local form, taken from mummies which have 
hung on the trees over winter, retain their power of germination. 
Chlamydospore measurements were made of spores from Soulard and . 
Longfield apples, from Harrison, Ocheeda, Newman, and Surprise plums, 
which were rotted in the laboratory, and from a culture on beerwort 
agar. In each instance 100 spores were measured, except in the case of 
the beerwort-agar culture, where 50 spores were measured. The results 
are given in Table I. 
