[Vor. 8 
42 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
The result is so clear as to leave little doubt of the suppression 
of growth and sclerotial formation owing to the sealing of the 
flasks. At the same time, however, it should be noted that at 
the close of the experiment the check flasks were always almost 
dry, so that the humidity conditions as well as the concentration 
were different from those of the sealed flasks. 
INOCULATION EXPERIMENTS 
Experiment 1 (a). (Inoculation of “navy beans" with various 
strains of Rhizoctonia).—A. number of bean seedlings, each in a 
pot of sterile soil, were inoculated with the 6 strains by placing 
some mycelium (all from potato cultures of the same age) near 
the plants about one-third below the surface of the soil. Twelve 
plants were inoculated with each strain. After a week “damp- 
ing-off" was noticed in the pots inoculated with P1 and H, 
9 plants being affected in each case. The strain Bl was also 
able to infect the host to a certain extent, as 3 seedlings were 
affected. The pots inoculated with P4, P7, and B3 were healthy 
after 2 weeks. 
(b). (Inoculation of navy bean plants with P1, B1, and H).— 
Young beans 7 inches high were pricked with a sterilized scalpel 
and inoculated with each of the 3 strains mentioned, 10 plants 
being used in each lot. All the plants were supported by bamboo 
sticks so as to grow erect. Many of the plants were affected, 
and with such old beans discoloration is observed not only on 
the infected stems but also on the roots, yet in no case were the 
plants killed. Pods were also affected, and through the sunken 
areas of these the hyphae penetrated the seeds and produced 
small sclerotia on the seed-coats. No distinction between these 
3 strains was noticed in symptoms nor in cultural characters. 
Experiment 2. (Inoculation of Lima beans with the six strains). 
—Young beans, 5 inches high, wounded by a sterilized scalpel, 
were inoculated with the 6 strains, 10 plants being used for each 
strain. After a week distinct reddish brown lesions of various 
sizes were produced just at the wounds of those plants inoculated 
with P1, B1, and H, while on the stem inoculated with P4 and 
P7 only very slight discoloration, with a light-colored sunken 
area, was noticed. In the check plants only brown punctures 
resulted, without any further development of lesions. In 
