594 Third European Journey 



commended, since he was convinced that the problem would have 

 to be solved by experimental methods. 



His study of the problem with plants did not end here. In 

 September of 1923, when agar poured plates taken from the base 

 of the fasciated Dahlia revealed " dendritic strongly iridescent 

 colonies, white, brownish, blue, or purple, according to the 

 lighting," he began taking some field notes and his memorandum 

 reads: ^® " It is a big double pink and the only fasciated pl[ant] 

 in 36 plates. I counted more than 50 fasciated blossom shoots 

 and no good flowers. Two fasciations have given 3-4 strop-shaped 

 pink petioles among the many green bracts." He photographed 

 these along with perfect flowers from the next plants in the row. 

 In April 1926 the Journal of Heredity ^^ published as its frontis- 

 piece of that issue two photographs entitled, " Fasciation of 

 Dahlia," with the following description by Smith: 



A full double pink Dahlia, one plant of which was fasciated as here 

 shown. This was a large much branched very leafy plant. There were many 

 floral axes stretched three to six inches and covered with green bracts. 

 There were no normal flowers on this plant, but occasionally a few pink 

 petals appeared, as on these two shoots. In addition to its excessive vege- 

 tative growth the plant differed visibly from its fellows only in having an 

 injured main axis into which rainwater had penetrated. This cavity 

 extending through several internodes was full of a mixed bacterial growth, 

 and the fasciation is attributed to the action of ammonia and other bacterial 

 by-products. Some of these fasciations were much more striking. One of 

 them had seven centers of growth at its apex. Types of the colonies ob- 

 tained on poured plates are also shown. There were at least three sorts, 

 yellow colonies, round white colonies and iridescent branched ones. Unfor- 

 tunately the cultures were lost before experimental inoculations could be 

 made. 



No later than 1918,*° he had stated his belief that " thyloses, 

 fasciations, distortions of tissues, and various duplications, sim- 

 plications and inverse tissue differentiations are caused by the 

 excretions of feeble parasites although in nature probably all are 

 not so caused." 



In 1923 Smith received some specimens of " early stages of 

 aerial galls on apple " which showed " dead buds as though the 

 swelling which is a root anlage might be started by death of the 



''Diary, Sept. 14, 18, 1923. 



*' 17(4): opposite p. 113, Apr. 1926. 



*" The relations of crown-gall to other overgrowths in plants, op. cit., 453. 



