PLATE i 
A. —Potato tuber cut to show transverse and tangential surfaces. 
B. —Radial section of tuber to show pith connections to bud. The red line indicates 
the location of the xylem part of the vascular tissue. Notice that the xylem is con¬ 
fined to a narrow ring, while the phloem is scattered throughout the tuber tissue. 
C. —Cortical cells from region just below a bud. The cells contain starch (violet), 
protein crystals (green) and tannin vesicles (orange yellow). 
D. —Protein bodies in sieve tube of young stolon. The cell to the left is a young 
sieve tube containing a nucleus and spiral bodies (spiral bodies and nucleolus colored 
red). Adjacent to the sieve tube is a companion cell and next to it a large parenchyma 
cell. Drawing is a reproduction of a preparation stained with methyl green and acid 
fuchsin according to Altmann. 
(836) 
