REPORT OF THE SOCIETY 67 



grew at the average rate of 6.3 mm. a day for the first six days after becoming 

 apparent to the naked eye. This organism apparently has a wide range of 

 temperature requirements. One fairly extensive test gave the best growth at a 

 temperature that was fluctuating between IGo and 19o. A later test with more 

 constant temperatures gave the most rapid growth at between 20 and 21o C. 

 These are only an indication, however, as the incubators are in constant use 

 for culturing other organisms and the opening and closing makes it impossible 

 to keep the temperature constant. Good growth has been obtained at tempe- 

 ratures ranging from 15 to 23oC. At 26oC and over the rate of growth declines 

 very rapidly. Some growth was obtained at 12oC, scarcely any growth at 

 280C, and at 33oC growth of the organism was inhibited quickly. 



As the colony develops on potato dextrose agar, it takes on first a reddish 

 shade that gradually darkens and becomes olivaceous black. The change in 

 color appears to be almost entirely due to a change in the color of the walls of the 

 developing pycnidia which are very abundant. On some other agars this dark 

 color is not so evident. Similar characteristics show an oatmeal agar. 



On an agar made from the stems of beans after the juice had been removed 

 the characters were much the same but on the agar made with the juice the 

 reddish color was the most prominent feature. 



The appearance of the colony varies with the environmental conditions, 

 a high temperature giving a black stroma-like colony and a low temperatmre 

 giving a thick dark ol ve-colored colony. Colonies moved into the laboratory 

 from a dark incubator proved to be sensitive to the light as the pycnidia formed 

 n rings. This zonation was evident in a colony grown on cornmea in the abo- 

 ratory. The co'onies show the spores, at the end of four or five days after 

 culturing, as pink masses on the surface. 



The colonies of this organism bear a striking resemblance to cultures of 

 C. lindemuthianum that were being grown at the same time especially as to the 

 pink masses of spores and the dark appearance of the colony. The pycnidia also 

 bear a resemblance to the small sclerotia that are developed in the Colletotri- 

 chum cultures. 



Artificial Inoculations. 



These have been made at various tinT.es throughout the late winter and 

 early spring on seedlings, plants in flower, and on plants where the pods were 

 half formed. Inoculations were made by spraying on the spores with an 

 atomizer or by placing a few drops of a spore suspension on the leaves. In 

 al: the experiments the conditions were the same as for inoculations with C 

 lindemuthianum some of which were also being carried on at that tune (moist 

 chamber for 48 hours at a temperature of 70F.) Smith in his inoculation expe- 

 riments used a medicine dropper and left the plant under a bell jar for from 3 

 to 10 days. Good infection was obtained in two days though it possibly might 

 be improved if left a little longer, especially if it means taking them out into 

 a d y atmosphere at the end of the 48 hours. The best infection was obtained 



