196 Sargant and Arber .— The Comparative Morphology of 
the trace. The identity of px Y with the scutellum xylem can be demonstrated 
by following sections downwards. That of phloem groups ph x and pH x 
with the scutellum phloem is not quite so clear, because during the trace- 
insertion, and for some distance above it, the limit between ph Y and ph 2 on 
one side, and that which divides ph\ from pH ^ on the other, is confused. 
Text-fig. 22. Coix La- 
cryi?ici-Jobi , L. a. Outline of 
young seedling, life-size. B. 
Husk of grain removed to 
show endosperm, c. Endo¬ 
sperm removed to show scu¬ 
tellum. 
Text-fig.23. Coix Lacryma-Jobi, L. a. Out¬ 
line of older seedling, life-size. B. Scutellum 
and adjacent parts, life-size. c. Endosperm 
from back, x 2. d. Endosperm from front, 
x 2. e. Scutellum from side. x 2. F. Scu¬ 
tellum from front, x 2. 
Starting from px Y as a fixed point, the structure of the mesocotylar 
stele is easily deciphered by reference to that of Sorghum and Zea. It is 
adequately shown in all four seedlings, and is symmetrical about the 
