136 



MORTIER F. BARRUS 



TABLE 4 (continued) 



It appears fairly evident that -spores of C. lindemuthianum removed 

 from the acervulus and remaining in the soil for a period of two weeks 

 or more are able to bring about an infection of susceptible bean seedlings 

 grown in such soil, but not after six and one-half weeks. Under field 

 conditions, however, in addition to spores being washed into the soil, 

 there are many bits of plant tissue, some of which would probably be 

 infected tissue, remaining on the soil after the beans are harvested. 



Frank (1883b: 521) tested the germination of spores which he found 

 produced in the lesions of dry seed. He concludes that spores attached 

 to the basidium remain viable throughout the winter, while those pro- 

 duced earlier and unattached are unable to survive. Edgerton (1910:25) 

 has studied in a different way the question of the viability of these 

 spores. He finds that the old spores on or within affected seeds are capable 

 of germinating in nutrient media, and suggests the possibility of the 

 infection of seedlings from healthy seeds by such spores, they having been 

 transferred to the healthy seed by contact with affected ones. He finds 

 also that good germination takes place in agar after the spores have 

 remained dried for thirteen days in their mucilaginous matrix or washed 

 free from it, and states that some germination took place after twenty- 

 two days had elapsed. 



