1012 Walter H. Burkholder 



strains of F. martii. The difference lay in intensity of color, greater or 

 less amount of aerial mycelium, and variations in the formation of pseudo- 

 pionnotes. Spore measurements made from the culture obtained from 

 the Wollenweber collection varied considerably from the measurements 

 given by Appel and Wollenweber and by Sherbakoff. The cultures from 

 the Centralstelle fur Pilzkulturen, however, agreed very closely with the 

 original measurements. Unfortunately the strain isolated from potato 

 by Dr. Sherbakoff was lost before spore measurements could be made. 

 Inoculation experiments, however, were conducted with all three strains 

 with the bean as the host plant. In no case did infection occur. It is 

 very improbable that these negative results are due to unfavorable con- 

 ditions, as positive results were always obtained at the same time with 

 the fungus from bean roots. There is no evidence that F. martii is para- 

 sitic on the bean root. 



From the foregoing statements it seems scarcely possible that the bean 

 Fusarium is identical with F. martii. There is a distinct physiological 

 difference, and possibly slight morphological differences. The latter are 

 so unimportant that the writer does not feel justified in using them as 

 the basis of a new species or even a new variety. Physiological differences, 

 however, have been used in this genus as the basis of new varieties. 

 Fusarium vasinfectum var. inodoratum Wr. differs from F. vasinfectum Atk. 

 only by the absence of odor. On the other hand, in other groups it has 

 been the custom, when the physiological difference was one of patho- 

 genicity, to treat the new form as a biologic species. For. this reason 

 the writer has used the trinomial Fusarium martii phaseoli. 



Since one strain of F. martii was isolated from a diseased pea root by 

 Dr. Westerdijk, there is the probability of another biologic species, F. 

 martii pisi. The writer, however, obtained no infections on the garden pea 

 when inoculations were made with F. martii. The original species appears 

 to be saprophytic. 



LIFE HISTORY 



The time of bean planting in New York State varies according to 

 weather conditions, but usually the seed is put into the ground in the 

 first half of June. The soil at that time is in a warm and moist condi- 

 tion. Thus as soon as germination of the bean seed takes place, external 

 factors are favorable for the infection of the young roots by the dry 



