56 CROWN-GALL OF PLANTS. 



January 19, 1910: Photographed natural size (PL X, fig. 2). 

 April 6, 1910: Galls are 2^ inches in diameter and still growing 

 (PI. X, fig. 3). 



GRAPE ON OPUNTIA. 



Inoculations of June 30, 1910 (Brown). 



Needle pricks from an agar streak 6 days old on one plant in one 

 group of punctures. 



Result. — October 21, 1910: Negative. 



GRAPE ON GRAPE. 



Inoculations of August 31, 1909 (Brown). 



Galled grape stems of the Champion variety were sent in from 

 Lawton, Mich., and agar plates were poured on August 23. A few 

 colonies appeared in 3 days, transfers were made, and from these grapes 

 and daisy plants were inoculated. 



Four grapevines (variety not known) in poor condition (no young 

 shoots being present) were inoculated, 3 to 5 stems on each, with 

 4-day-old agar cultures. 



Result. — October 13, 1909: Two of the 4 plants inoculated were 

 covered with the smah warty protuberances characteristic of grape 

 gaU (PI. X, fig. 1). 



Inoculations of September 7, 1909 (Brown). 



Inoculated 6 young grapevines, several stems each (Seedless Sultana 

 variety), with the grape-gall organism, cultures 3 days old. The vines 

 were in pots and in fairly good condition and were inoculated in the 

 youngest parts. Two plants were held as checks. 



Result. — September 25, 1909: All of the inoculated plants had galls 

 of the typical grape-gall kind. The checks had no galls. 



GRAPE ON ALMOND. 



Inoculations of March 27, 1908 (Smith). 



Three young shoots of almond were inoculated copiously by means 

 of needle pricks from 48-hour slant agar cultures (same as used on 

 daisy of this date which failed), the organism being derived from tumor 

 on grape occurring in this country. 



Result. — June 1, 1908: The shoots have grown much since the date 

 of inoculation, but as yet have developed no tumors. 



December, 1908: None appeared. Possibly wrong organism 

 selected. Certainly there are sometimes noninfectious white schizo- 

 mycetes in the galls which on agar are very difficult to distinguish 

 from the right organism. 



213 



