3 < 3 o 
Journal of Agricultural Research 
Vol. II, No. s 
same way but produced in the field at Amarillo in 1911 showed 6.4 per 
cent of infection. The high winds had torn some of the bags at times, 
but they were replaced as soon as possible. Moreover, four of them 
remained intact throughout; yet of the 206 plants grown from the 
resulting seed, 13, or 6.3 per cent, were infected. This was scarcely less 
than the average natural field infection in 1912. (See fig. 7.) 
This evidence is a particularly strong negation of the floral infection 
theory, especially when it is noted that the seed lot from the greenhouse 
in Washington, D. C., produced 8 infected plants out of 18 when the 
seedlings were artificially inoculated. (See Table V, plat C, No. 5.) 
INFECTION EXPERIMENTS 
It has been made clear by the results already described that floral 
infection is not involved in the life history of this parasite and that seed- 
borne spores, though doubtless functioning at times in distributing the 
fungus from one district to another, by no means constitute the determin¬ 
ing factor in the general field infection. The apparent contradiction in 
the evidence so far presented—one which has led to many confusing 
surmises and recommendations in the literature of the subject—remains 
to be explained by positive evidence of infection from artificial 
inoculations. 
A series of inoculation experiments carried on at Amarillo, Tex., in 
1911, duplicated at Amarillo, Tex., at St. Paul, Minn., and at Manhattan, 
Kans., during the season of 1912, and twice repeated in the greenhouse at 
Washington, D. C., has confirmed these observations and demonstrated 
that the presence of the parasite in the soil about the growing seedling is 
productive of successful infection under any of the conditions prevailing 
in these various habitats. These results are presented in Table V. 
EXPLANATION OP TABLE V 
In tabulating these results considerable abbreviation has seemed desirable, and 
it is herewith explained. When special reference to this explanation is necessary, 
the abbreviations in Table V are inclosed in parentheses. Under each of the follow¬ 
ing main headings the column with the same heading in the table is explained. 
“Date.”—The date given in the column provided is the date of inoculation except 
in a few cases, usually controls, when it is inclosed in parentheses and indicates 
the date of planting. 
“Seed Lot.”—Five different lots of seed, all of the variety Red Amber sorgo (S. P. I. 
No. 17548), were used and are indicated, in the column provided, by the following 
symbols: 
“ I. ” From the crop of 1910 at Amarillo, Tex. When in parentheses, as “ (I), ” 
the seed had the glumes still inclosing it; otherwise it was without them, having 
been separated in water from the seed which had retained the glumes through the 
thrashing process. 
“ II. ” Seed without glumes (separated in water, as in I); from the crop of 1911 
at Amarillo. This seed was treated with a 0.24 per cent formaldehyde solution 
for one hour, except where the symbol is in parentheses “ (II). ” 
