NortH Haven SAanp PLarns 599 
Central portion of root is composed of mostly empty cells which 
appear circular in cross-section and have fairly thick walls with 
intercellular spaces at the angles. Structure is practically the 
same as is shown in the figure of A. furcatus (pl. 27, @). 
ANDROPOGON FURCATUS.— The central portion of the root is 
made up of rather thick-walled pitted starch-cells, which are 
nearly circular in transverse section, 7. ¢., their lumina are circular 
and nearly uniform in size. The vessels are arranged in a circle 
having a diameter two thirds as great as that of the root-section. 
The roots examined contained eighteen vessels, the largest ones 
having a diameter of only 34. Diameter of root is 1 millimeter. 
Just outside of the circle of vessels and sometimes alternating with 
them are the small patches of phloem elements. The endodermis 
has peculiar cells with the inner walls much thickened and pitted. 
Between the endodermis and the phloem region are starch-cells 
resembling those of the central portion except that the walls are 
thicker and more strongly pitted. This tissue corresponds to the 
sheath or pericycle but is not of the structure usually found in 
bundles. The larger vessels are the only portion of the xylem 
elements that can be made out in cross-section. The cortex is 
composed of four or five layers of thin-walled cells resembling cork, 
which are mostly empty and appear oblong in a cross-section of 
the root. 
The rootstock is thickened at the nodes (see f/. 27, ¢), and 
these nodes are composed chiefly of rather thick-walled paren- 
chyma-cells crammed with starch granules. These cells are 
nearly circular in cross-section and larger than the corresponding 
cells of the root. The vasculat bundles penetrate this tissue at 
nearly equal distances and seem to extend in all directions, for 
bundles cut transversely, longitudinally and obliquely occur in the 
Same section. These have been deflected at the thickened nodes 
and are parallel between the nodes. The starch-cells are usually 
larger than the vessels of the bundles. The latter are made up of 
long pitted cells. The cortex is thin and is made up of paren: 
chyma with cells much smaller than those of the central portion 
and packed less closely with starch-granules. The endodermis 
Surrounds the entire central portion of starch parenchyma-cells 
and bundles and its cell-walls are thickened on the inner side. 
