ROOTS 45 
than in the older and larger portions of the root. Sketch one section 
of each kind. 
Examine with a higher power (100 to 200 diameters), and note the 
ends of the thick-walled wood-cells. Compare these with Fig. 72. 
Notice the many thinner-walled cells composing stripes radiating 
away from the center of the root. These bands are the medullary 
rays, Whose mode of origin is shown in Fig. 68. Moisten some of 
the sections with iodine solution,! and note where the blue color 
shows the presence of starch. Split some portions of the root through 
the middle, cut thin sections from the split surface, and examine with 
the high power some unstained and some stained with iodine. 
Notice the appearance of the wood-cells and the ducts as seen in 
these sections, and compare with Fig. 58.? 
56. Structure and Contents of a Fleshy Root. — In some 
fleshy roots, such as the beet, the morphology of the parts 
is rather puzzling, since they form many layers of tissue 
in a single season, showing on the cross-section of the root 
a series of layers which look a little like the annual rings 
of trees. 
The structure of the turnip, radish, carrot, and parsnip 
is simpler. 
Cut a parsnip across a good deal below the middle, and stand the 
cut end in eosin solution for twenty-four hours. 
Then examine by slicing off successive portions from the upper 
.end. Sketch some of the sections thus made. Cut one parsnip 
lengthwise and sketch the section obtained. In what portion of the 
root did the colored liquid rise most readily? The ring of red marks 
the boundary between the cortical portion and the central cylinder. 
To which does the main bulk of the parsnip belong? Cut thin 
transverse sections from an ink-stained parsnip and notice how the 
medullary rays run out into the cortical portion, and in those sections 
1 If the roots are in their winter condition. 
2 The examination of the minute structure of the root is purposely made 
very hasty, since the detailed study of the structural elements can be made to 
better advantage in the stem. 
