218 Tue Microscope. 
The cambium is composed of several rows of brick-shaped 
or tabular cells, separating the bark from the wood. They are 
clear white, with exceedingly thin walls, and contain only pro- 
toplasm. 
The medullary rays are quite wide, and composed of a 
number of rows of parenchymatous cells, stronger and thicker 
walled than the cambium cells, and loaded with starch grains. 
The pith has the usual appearance of large, hexagonal cells 
of parenchyma, loaded with starch grains. 
The woody bundles between the medullary rays, the cam- 
bium and the pith, are not fully developed. There are a few 
small reticulated cells, with pointed ends, and surrounded with 
a small amount of prosenchyma and considerable parenchyma. 
The reticulated cells have thick walls, and are not parallel with 
the surface of the rhizome; so it is quite difficult to obtain a 
good longitudinal section of them. The prosenchyma is in 
clusters around the reticulated cells, and is of a bright yellow 
color. 
Every part of the rhizome, excepting the cork and woody 
bundles, is loaded with minute starch grains. These are nearly 
round, with no distinct rings or nucleus, and about 1-4000 of an 
inch in diameter. Occasionally they are found in groups of 
three, like the starch grains of sarsaparilla. 
In the center of the root is a woody bundle. It is not per- 
fectly developed, and often four clusters of reticulated cells are 
placed equal distances from each other. At the very center is 
found a small amount of wood parenchyma. The cells of the 
prosenchyma found in the woody bundle are short, and with thin 
walls. Surrounding the woody bundle is a single row of paren- 
chymatous cells, with the inner wall frequently thickened like 
stone cells. This row is slightly tinged with yellow, and closely 
resembles the nucleus sheath of monocotyledonous roots. 
The principal bulk of the root is found outside of the 
woody bundle, and is composed of simple parenchyma loaded 
with starch grains. This tissue occupies fully four-fifths of the 
entire root. On the outside of this parenchyma, and surround- 
ing the entire root, are two or three layers of dark brown, 
brittle, empty cells, closely resembling the cork cells of the 
rhizome. 
