32 



BACTERIAL DISEASES OF PLANTS 



FIG. 22. Colonies of Bacterium iranslucens var. undulosum S., J. R., the cause of 

 black chaff of wheat. Same as Fig. 21 but three days later. At the upper right 

 side of the lower colony, lifted above the surface of the gelatin, is a bacterial tendril 

 which has made 6 turns. X 85 



