138 



Sorghum (Holcus sp.). There was 100% infection of both roots 

 and stems, with pronounced rot. T he same phenomena were observed as on 

 wheat, including the appressoria, penetrating mycelium, and "callus." 

 The sap of the infected cells was strongly tinged with red,_and the ' 'cal- 

 lus" and appressorium were deep red. Adjacent colorless walls soon be- 

 came swollen and reddened. The red coloring-matter is absorbed by the 

 nucleus, which becomes as brilliantly colored as by an aniline dye. At six 

 days the shoots and roots were heavily infected, the diseased regions 

 assuming a deep red, almost black, color, and conidia formed abundantly 

 over the lesions. When such specimens were placed in alcohol, the red 

 color diffused to the alcohol, coloring it strongly. This red coloration 

 by the host is a response common on invasion of either bacteria or fungi 

 on the sorghums and sugar-cane, and on corn in the case of some diseases. 



Sudan grass (Holcus sorghum sudanensis) . At ten days 1 seedling 

 gave positive and 5 gave negative results; at six days, 5 positive and 4 

 negative. Infection was slight on a few cells, but the mycelium was evident 

 within the cells, and infection phenomena as on wheat were observed. 



Common millet (Chaetochloa italica). At two days 10 gave positive 

 results. At six days the rot was progressing into the roots faster than 

 into the stem, though black spots 3 4 cm. long were apparent. Infection 

 phenomena were observed as on wheat, and much mycelium was seen 

 within the tissue. 



German millet (Chaetochloa italica germanica). The results were prac- 

 tically the same as with common millet. 



Amber cane (Holcus sorghum]. Results were much as on sorghum. 



Red top(Agrostis palustris). No phenomena of infection were observed . 



Beans. No rot was produced, no "callus", nor any other of the usual 

 signs of infection; nor was it certainly determined that the mycelium 

 entered the host-cells, though it seems probable that the fungus killed 

 some of the bean cells. 



Inoculation of leaves. Pots of well-established seedlings of wheat, 

 oats, rye, barley, corn, German and common millet, and sorghum were 

 placed in a humid atmosphere (above 90% relative humidity) and atomized 

 with suspension of H. No. 1 conidia. Well-defined spots occurred fre- 

 quently on barley, less frequently on wheat. Leaf-spots due to a Helmin- 

 thosporium, apparently H. No. 1, also occurred naturally on wheat in the 

 greenhouse. Such spots were first pale; later with a mummified dark 

 center surrounded by a pale zone; and were oval in outline. In rye the 

 mycelium was seen to be abundant within the cells, and complete death 



