10 



Mycologia 



Literature Cited 



1900. Tourney, J. W. An inquiry into the cause and nature of crown gall. 

 Bull. Arizona Agri. Exp. Sta. 33: 7-64. /. 1-31. 



1901.1 Hedgcock, G. G. Field studies of the crown gall of the grape. Bureau 



Plant Ind. U. S. Dept. Agri. Bull. 183 : 1-40. pis. 1-4. 



1910.2 . Field studies of the crown gall and hairy root of the apple tree. 



Bureau Plant Ind. U. S. Dept. Agri. Bull. 186: 1-108. pis. 1-10. 



191 1. Smith, E. F., Brown, N. A., and C. 0. Townsend. Crown gall of 



plants, its cause and its remedy. Bureau Plant Ind. U. S. Dept. Agri. 

 Bull. 213: 1-215. pis. 1-35. 



19 1 2. Smith, E. F., Brown, A. N., and L. McCulloch. The structure and 



development of crown gall. Bureau Plant Ind. U. S. Dept. Agri. Bull. 

 2 55 : 1-60. pis. 1-109. 

 19 1 6. Smith, E. F. Further evidence that crown gall of plants is cancer. 

 Science N. S. 43, No. 1121: 871-889. 



1918. Levin, I., and M. Levine. Malignancy of the crown gall and its analogy 



to animal cancer. Proc. Soc. Exp. Bio. and Med. 16: 21-22. Jour. 

 Cancer Research 5: 243—260. f. 1—15. 1920. 



1 9 19. Levine, M. Studies on plant cancers I. — The mechanism of the forma- 



tion of the leafy crown gall. Bull. Torrey Bot. Club 46 : 447-452. 

 pis. 17-18. 

 1646 University Avenue, 

 New York City. 



Explanation of Plates i and 2 



Fig. 1. Represents the type of Ficus elastica used in these experiments. 

 The galls in the various parts of the plant a, b, c, and d are the result of inocu- 

 lating them with a culture of Bacterium tumefaciens, five months previously. 



Fig. 2. Apical portion of a branch showing a large crown gall seven 

 months after inoculation in the second internode. The gall does not seem to 

 have interfered with the growth of the stem; several internodes having been 

 added in the interim. (X ^2.) 



Fig. 3. Same branch twelve months after inoculation. The leaves above 

 the gall have dropped off. The stem is discolored, dry, and dying progressively 

 upward. The tip is still green and alive. The gall is hard, dry and dead. 



(x y 4 .) 



Fig. 4. Cross section of the stem through the gall shown in figure 3. The 

 wood cylinder is only partially destroyed by the invading gall. The portion 

 of the crown gall near the central cylinder is soft and disintegrating. 



Fig. 5. Longitudinal section of the upper portion of the same stem. The 

 portion near the gall is dry, brown and dead, while the apical internode and 

 bud are still green and alive. 



Fig. 6. A branch of Ficus elastica in which the gall and the stem above 

 and below the gall is dead ; the inoculation having been made twelve months 

 previously. 



Fig. 7. Longitudinal section showing invasion of the crown gall destroy- 

 ing a considerable portion of fibrovascular bundles. The invading portion of 

 the gall is soft, spongy and disintegrating. 



