Dec, 1921] 
LEVINE — STUDIES ON PLANT CANCERS 
but the crown galls were proportionately small as compared to the size of 
the root. Figure 7 represents a series of beet roots grown in plot "SW/* 
photographed at maturity when the plants were harvested; in this series 
the smallest crown gall was smaller than a pea while the largest was about 
the size of a black walnut. 
Fig. 5, A, B, C, D. A series of crown galls on the roots of the garden beet grown in 
fertilized soil; one month after inoculation. Fig. 6, A, C. Cross sections of the roots 
shown in figure 5, A and C. Fig. 7. A series of crown galls on garden beets grown in 
poor soil. Inoculation made August 11, 1920. Photographed October 16, 1920. 
My observations on the appearance of the crown galls grown on these 
varieties of the garden beet are not in complete accord with those of Jensen, 
who claims that tumor-like growths on the different varieties of the garden 
beet differ from one another both in appearance and structure. In my 
cultures all the common t^^pes of crown gall appeared in each variety. 
Figure 5A represents the smooth type, 5B a warty gall, and 5C and 5D 
represent mixed types (smooth and warty), a form which Jensen does not 
recognize. In the mangel wurzel described below and shown in figure 9, 
we have similar types. The warty and the smooth types appear here as 
does the mixed type. It is of interest to note that crown galls of the smooth 
and warty types are also found in artificially produced crown galls on 
Ficus elastica (Levine, 192 1.) The significance of these different types of 
crown gall is not yet perfectly understood. 
In my observation of the galls on the Early Model and Egyptian Early 
