Abnormal Growth 



291 



them the name by which they are now commonly known, cataplasmatic 



galls. 



Crown Gall. Here belongs the gall that has been studied more inten- 

 sively than any other, crown gall (Fig. 11-10). This is produced on a 

 wide variety of plants, at least 142 genera in 61 families, by the bacterium 





Fig. 11-10. A crown gall on sunflower. (Courtesy Department of Plant Pathology, 

 University of Wisconsin. ) 



Agrobacterium tumefaciens. There are reviews of work on such galls by 

 Levine (1936); Riker, Spoerl, and Gutsche (1946); de Ropp (1951a); 

 Klein and Link (1955); and Braun and Stonier (1958). Crown gall has 

 been investigated by Erwin F. Smith and his colleagues ( 1911, 1917, and 

 many others) and later by various botanists among whom Braun, 



