Mar. 25, 1914 
Imperfect Fungi from Wheat , Oats , and Barley 
481 
planting, the whole seed often was permeated by the fungus, the contents 
of the seed coats having a pink coloration. The plants which survived were 
discolored at the base in a manner similar to those of plants from seed 
inoculated with Helminthosporium gramineum. Where discolorations oc¬ 
curred, it was the first leaf sheath which was affected, while the central 
stem or culm was normal in appearance and color. The vigor of the 
plants from inoculated seed was markedly reduced, and they were shorter 
than the normal plants during the six weeks in which they were grown. 
This was true also of wheat and barley grown from seed inoculated with 
this fungus. 
COMPARATIVE ROOT DEVELOPMENT OF WHEAT PLANTS GROWN FROM 
SEED INOCULATED WITH HELMINTHOSPORIUM GRAMINEUM AND 
FROM CLEAN SEED 
To determine the comparative development of the root systems of sur¬ 
viving plants from seed inoculated with Helminthosporium gramineum 
and from clean seed, two pots of wheat containing five plants each, one 
grown from inoculated and the other from clean seed, were removed 
to the laboratory and the soil carefully washed away from the root sys¬ 
tems. The roots were spread out by floating them in water and then 
drawing off the water. The difference in development of the root 
systems of the two sets of plants was very marked. The roots of plants 
from inoculated seed were discolored near the root crown. They were 
also much shorter and much less vigorous than roots of plants from clean 
seed; this is strikingly shown in Plate LXIII. Numerous other plants 
were examined, and it was found that in practically every case where 
inoculated seed had produced plants which survived, the root systems 
were less vigorous than in plants grown from clean seed. 
SOIL INFECTION WITH HELMINTHOSPORIUM 
To determine whether or not soil in which seed inoculated with Hel¬ 
minthosporium gramineum had been planted would remain sufficiently 
infected for any length of time to injure later plantings, inoculated seed 
was planted in pots in the greenhouse at Washington, D. C., on November 
21,1911, and the resulting plants were grown for five weeks and then cut 
off. Control pots were similarly planted with clean seed and the plants 
removed after five weeks. These pots were again sown on January 13, 
1912, with wheat which had been previously sterilized in a 2.5 to 1,000 
formalin solution. Of 150 seeds planted in the soil in which wheat plants 
had been grown from seed inoculated with H . gramineum , 104, or 69.3 
per cent, germinated and produced plants, while of 90 seeds planted in 
control pots 76, or 84.4 per cent, germinated. This indicates that the 
soil remained infected during the two months in which the experiment 
was in progress. How long soil remains infected in this way is one of 
the important problems in plant pathology. 
28736 0 —14-4 
