Jan. 19, 1924 
Anatomy of the Sweet Potato Root 
159 
(PI. 1 A and fig. 3.) Occasionally an additional small vessel is formed 
adiacent to the large one. , „ „ , , 
Following the differentiation of this large ‘ central cell and the ™ rma “ 
tion of an area of actively growing tissue between the central cell and 
Thr * -Cross section of a young fleshy root. A. cortex; B. endodermis; C, pericycle; D, phloem; E- 
^ cambium; F. proto-xylem group. Drawing is a copy of an enlarged photomicrograph. 
the protoxylem groups, the differentiation of a cambium takes place. 
This cambium, lying outside of the xylem and inside of the phloem 
gradually forms a complete cylinder. The outline of this cylinder is at 
first very irregular (fig. 3)1 partly because of the radial arrangement 
of the vascular tissue and partly because of local cell increase m the 
