EXERCISE 43 



Problem. What is the structure of a fleshy root ? 



What to use. A good-sized fleshy root (for example, carrot or parsnip) ; 

 glass ; eosin or red ink ; water. 



What to do. Place tip of root in dye; let it stand for twenty-four hours, 

 then -make a few thin cross sections and cut a few long sections. Find the 

 epidermis, or skin, and the central cylinder, or wood. A portion between the 

 epidermis and central cylinder is called the cortex, or bark ; a cylindrical layer 

 of cells between cortex and central cylinder is the actively growing portion, 

 the cambium layer. Extending from the cambium toward the skin and toward 

 the center are the medullary rays. 



Record. Make a drawing of the cross section, two inches in diameter, and 

 one of the long section ; label all the parts named in the study. 



Questions. 1. From specimen studied, along what paths do you think liquid passes upward through 

 the roots ? 



NOTE. Plants like parsnip, carrot, etc. usually grow a large root and a head of leaves from the seed during the first 

 season. During the following winter the root remains in the ground and the part aboveground dies away. With the second 

 season a flower shoot develops rapidly and the fruit and seeds are formed at the expense of the food accumulated in the root 

 the first season. 



2. Why is the best time to gather fleshy roots for human food late in the fall or early in the spring ? 



3. Why should roots be stored in cool and dry places ? 



4. What advantage has a plant like the dandelion over those that start anew from seeds every 

 season ? 



5. If microscopic preparations of small roots such as Ricinus (castor-oil plant) can be had, make 

 microscopic study and compare with gross structure. 



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