598 Third European Journey 



on a larger scale in 1925 with the same results. It is the first time I have 

 observed cysts in connection with crowngalls. 



On June 18, 1925, Smith inoculated " about 90 sunflowers . . . 

 in the small undeveloped flower head hoping to get again strop- 

 flowers in center of the heads." By July 15 the five or six heads 

 " smallest when inoculated " showed " large green bracts in the 

 center " and would, he believed, later " show central strop shaped 

 flowers." Two days passed, and twenty of the inoculated plants 

 showed " large central green bracts and the beginnings " of the 

 phenomenon. He wounded eighty side buds of small heads in 

 the center with a scalpel and in each case cut out a central piece 

 of the torus to see whether again he could get any result. By July 

 18 one of the " strop shaped yellow flowers " had opened and, on 

 dissecting it, he found " a little crowngall tissue in the extreme 

 top of the stem under [the] bracts and also one small central 

 white lobe distorted with tumors but," wrote he, " there seems 

 hardly enough to account for the results. Can it be due solely to 

 the wounding? The distorted tumefied piece" was then "fixed 

 in alcohol." July 22 he " got very striking results in one head, 

 viz. a second small head developed in the middle of the large one." 

 He dissected two inoculated sunflower heads that showed no 

 central proliferation, were not split open, and had no tumors on 

 or in the stem, but did have tiny ones on the torus. By July 25 

 his memorandum read: " There are many long tumor strands in 

 the stems of the proliferated sunflowers. It seems hardly possible 

 the 14 to 19 inches of strand is all due to stretching of stem under 

 the young head and no invasion, but most of it may be." Within 

 three more days twenty-four of the eighty-eight sunflowers had 

 proliferated in the head and he saw " in the pith of stems under 

 the head long cyst-like cavities lined like the torus with a soft 

 hairy membrane. These cysts," he noticed, " often bear tumors on 

 their walls and are subtended by a ring of vascular bundles, a 

 dozen or more with xylem outermost and phloem turned toward 

 the cyst cavity." 



What he had learned from these experiments he itemized in a 

 memorandum of July 31: 



(1) have found many stems in the pith extending down long distances, 

 (2) have found pith cysts lined by a hairy membrane like that of the torus 



