172 



The Microscope. 



Fig. 4. 



cellulose in their thick wall. These are about ^ of an inch 

 long, and have many radiating lines or breaks, as seen in the 

 longitudinal section. 



The woody part of the rhizome is composed of poorly de- 

 veloped medullary rays, wood prosenchyma, and pitted cells, 



with a few spiral vessels ; all colored 



bright yellow. 



The pith in the center of the rhi- 

 zome is composed of very thin-walled 

 oval cells of parenchyma, loaded with 

 starch grains. Occasionally a modified 

 cell is filled with coloring-matter. 

 Around the outside edge of the pith 

 are a few parenchymatous cells hav- 

 ing distinct reticulated marks (see 

 Fig. 2, i, and Fig. 4). Many of the 



A single cell from the par- ° ' ' ° ' J 



enchyma of the pith with re- cells of the parenchyma, both at the 

 ticuiated markings. Drawn cen ter and the outside of the rhizome, 



with the J$n. objective and the 



" A" eye-piece. have faint reticulated marks, which 



show both on the cross and longitudinal sections. 



Root. — The root 

 is surrounded by 

 many fine root-hairs, 

 in which is found a 

 small amount of pro- 

 toplasm. The most 

 of the root is com- 

 posed of large, thin- 

 walled, oval cells of 

 parenchyma. The 

 most of these contain 

 minute starch-grains 

 ( see Fig. 6), and some 

 of the larger cells con- 

 tain coloring-matter 

 and oil. 



In the center of 



Fig. 5. Cross section of the root. Drawn with the 

 the root is found the %-in. objective, and the " C" eye-piece. 



