PI/ATE 2 
A. —Longitudinal section through vascular ring of mature tv 
B. —Starch grains from the variety Irish Cobbler. X125. 
C. —Starch grains from the variety Green Mountain. X125. 
D. —Protoxylem elements from mature tuber. X125. 
E. —Secondary xylem vessels from mature tuber. X125. 
X129. 
