THE CROWN gall: HISTOLOGY 



467 



Fig. 355. — Advancing margin of crown-gall tumor in the soft white pith of a 

 sunflower disk Tumor hard grayish green and exceedingly vascular because 

 derived from the very vascular torus (seed -receptacle). The white parts at the 

 left are surrounded and compressed pith cells. Slide stained with acid fuchsia 

 and counterstained with methyl green. Pith white, vessels (tracheids) blue, 

 tumor tissue red. Consult also Jour. Cancer Research Vol. I, No. 2, Plate XIII, 

 Fig. 52. 



