STEWART: TUBERS OF SOLANUM TUBEROSUM 



425 



To one familiar with Gager's interesting paper^ on ingrowing sprouts of 

 potato tubers it appeared probable that tubers forming on ingrowing 

 sprouts had enlarged until the pressure produced became sufficient to 

 rupture the tissues of the parent tuber. Upon dissection of the 

 tubers this was found to be true. 



Fig. 3. The specimen shown in Fig. 2 with one side cut away to show the 

 origin of the ingrowing sprout which bears the new tuber. A slight change in pose 

 has brought to view a second new tuber. Nat. size. 



The old tuber shown in Fig. 2 was carefully dissected to determine 

 the origin of the sprout bearing the new tuber which was emerging 

 from a slit at the bud end. It was found to have started from the 

 "eye" on the right side of the old tuber where the two external, sessile 

 new tubers are seen. Fig. 3 shows the same tuber, in a slightly 

 different position, with the tissue cut away so as to expose the new 

 tuber and the sprout bearing it. In accomplishing this one of the 



^ Gager, C. Stuart. Ingrowing sprouts of Solanum tuberosum. Bot. Gaz. 54: 

 515-524. 1912. 



