PLATE 41 
Ontogeny of the potato: 
A. —Radial section of potato eye and part of mother tuber showing amount and 
position of procambium. X 5-4- 
B. —Transverse section through tip of potato, stem, showing the general distribu¬ 
tion of tissues, the amount of vascular tissue, and its arrangement into groups. X 39 . 
C. —Transverse section through growing region of potato eye, showing the first 
visible differentiation of internal phloem groups. X 414. 
D. —Transverse section through tip of potato eye, showing the arrangement of the 
various parts and the beginning of vascular differentiation. X 22. 
