Nov. 15,1915 
Sclerotinia Spp. on Ginseng 
2 93 
During a rainy period infection is evident within a much shorter time. 
All attempts to produce the disease without previously injuring the 
root gave negative results. 
IDENTITY OF THE SPECIES 
In order to further prove that the species of Sclerotinia from ginseng 
is identical with Sclerotinia libertiana Fuckel, a comparison was made 
with cultures from different sources. In addition to the four strains 
mentioned above, there was also used a pure culture isolated by Dr. 
Donald Reddick, of Cornell University, from celery. The comparison 
of the strains consisted in (1) growing the cultures on different media, 
both acid and alkaline; (2) production of apothecia, measurements of 
asci, ascospores, and a study of the manner of germination; (3) cross- 
inoculations on lettuce. These topics are briefly discussed in the follow¬ 
ing paragraphs. 
Growth on different media. —Cultures were made on potato agar, 
nutrient agar, bean plugs, ginseng stems, and Raulin’s synthetic fluid. 
In the case of potato and nutrient agar both acid and alkaline media 
were used (±10.5 Fuller’s scale). On all the media the various strains 
made a good growth, but no differences were visible. 
Production of apothecia, etc. —In order to obtain apothecia from 
the various strains, the sclerotia produced in pure culture were placed on 
sterile moist sand in dome-shaped preparation dishes. The sclerotia 
were covered with a very thin layer of the sand, and the dishes were 
placed on a shelf in front of a window. The time required for these 
apothecia to develop varied greatly, the limits being from three weeks 
to three months. The size of the apothecia likewise varied even in the 
case of sclerotia from the same strain and produced in the same test 
tube. However, the apothecia were alike in general appearance in all 
the strains. Plate XXVIII, figure 3, shows apothecia from the celery 
strain, and Plate XXVIII, figure 4, shows the same from the ginseng 
strain. A large number of measurements made of asci, paraphyses, 
and ascospores showed no marked variations, and agreed with the 
description of Sclerotinia libertiana Fuckel as given in Saccardo. In 
figure 1, A, is shown a camera-ludda drawing of asci, ascospores, and 
paraphyses from a fresh preparation of the Mentor strain. 
Crushed pieces of apothecia were placed in drops of water in order to 
observe the ascospore germination. Within four hours after being placed 
in water the first signs of germination became visible. Figure 1, B, shows 
the ascospores within the asci, germinated by sending germ tubes directly 
through the walls of the ascus. No differences were noted in the germi¬ 
nation of the spores from the different strains. 
Inoculations on lettuce. —Mature lettuce plants were selected and 
inoculated with the various strains of the fungus. Inoculations were 
