NortH Haven Sand PLains 603 
radially, the transverse section showing six points. Endodermis 
distinct, of rather thick-walled cells except those cells opposite 
the xylem rays which have thin walls, probably for the purpose 
of transferring water between the bundle and the parenchymatous 
tissue. Central cylinder is surrounded by a large mass of paren- 
chyma-cells having thin walls and containing no starch. 
Diameter of root, .78 mm. 
«* © central cylinder, -18 mm. 
“ ‘* largest vessels, 40 u 
Rhizome: consists of large thin-walled parenchyma-cells in 
which tissue the concentric bundles are rather irregularly arranged. 
Vessels of the bundles are much smaller than the parenchyma- 
cells surrounding the bundles. A few cells contain large bundles 
of raphides or acicular crystals. Cells of outer portion somewhat 
smaller than those in central part and contain smaller crystals. 
Endodermis not apparent. The structure of a small root is shown 
on fl. 28, a. 
VAGNERA RACEMOSA. — Root: bundle arranged radially with 
nine points, nine phloem patches and six large vessels. Endo- 
dermis distinct, of cells rectangular in cross-section, and with 
thicker walls than the cells of the surrounding tissue. Opposite 
the xylem points, the thick-walled endodermal cells are replaced 
by thin-walled cells, thus making a connection between the xylem 
and the cortex. The cortex is composed of very large thin-walled 
parenchyma-cells with intercellular spaces. 
Diameter of root, 1.25 mm. 
ad “< central cylinder, -39 mm. 
re ** largest vessels, 66 ju 
Rhizome : central tissue is made up of large thin-walled cells 
with many intercellular spaces. The bundles extend through this 
tissue at quite regular distances apart and are of the type found in 
Liliaceae and other monocotyledons with phloem enclosed in a 
xylem sheath of thick-walled pitted vessels. Endodermis com- 
posed of small cells. Certain large cells in the central portion 
Contain bundles of raphides. Cortex is composed of large circu- 
lar parenchyma-cells. Whole structure of roots and rhizome 
much like that of Sa/omonia biffora, to which it is closely allied. 
