PLATE 36 
Distribution of tissues of the potato: 
A.—Transverse section of lateral bundle of mature petiole, showing distribution of 
external and internal phloem and amount and arrangement of xylem. X 39 6 - 
B } D, E.—Cross sections through leaf blade at different stages of development, 
showing differentiation of palisade layer and spongy parenchyma. X 3 6 9> 342 , 405, 
respectively. 
C.—Transverse section of petiole, showing arrangement of vascular tissue, amount 
of cortex, and distribution of collenchyma. X 42. 
