Pky l log! os sum Drummondii , Kunze, 321 
In higher sections this solid mass of xylem decreases rapidly in size 
(sect. 4), and finally dies out (sects. 3 and 2). 
The bearing of these facts on the relation of the tuber to the main 
axis is clear from the vertical plan of the stele given in Fig. 4, A, which 
shows the relative position of the sections just described. On the right- 
hand side of the diagram is a large tuber, the stele of which makes a 
sharp upward bend before passing out and down the shaft of the tuber. 
The result is that sections below the bend cut the tuber stele in two 
places (sect. 6), while sections at a higher level cut the bend itself, and, 
therefore, show but a single mass of xylem (sects. 5 and 4). The collec- 
tion of isolated tracheides in sect. 3 represents the highest part of the bend. 
The most important features in the stelar anatomy of the plant 
considered may be summed up as follows : At the base of the plant 
