CHAPTER IV 

 ' ROOTS 



The root system is the part of the plant which, is usually 

 located in the soil and serves pirimarily for anchorage and for 

 the absorption of water and mineral food materials which are in 

 solution in the water. However, the location below the ground 

 is not a distinctive character of roots, for it must be remembered 

 thaA some plants have roots above the soil and that some plants 

 have underground stems. A much better distinctive character is 

 that roots are not divided into nodes and internodes, as in the 

 case of stems. Therefore, stems usually branch regularly from 

 the nodes, while the roots branch very irregularly. 



Types of Root. — Roots may be very generally divided into 

 two groups : tlie fibrous and the fleshy r&ois dependent on their 

 character and also into primary and secondary roots dependent 

 on their location. The fibrous roots (Figs. 35 and 37) are more 

 or less woody and are characteristic of most of the higher plants. 

 In the case of large plants the roots are usually very large and 

 very woody. The roots of some trees produce a beautiful wood, 

 which is highly prized for cabinet-making. The fleshy roots 

 (Figs. 36 and 37) contain the woody elements or fibro-vascular 

 bundles, but they also contain large amounts of parenchyma 

 tissue and therefore serve for storage of water and other 

 food materials. They are always associated with fibrous roots, 

 which serve primarily as organs of absorption. Turnips, radishes, 

 beets and similar plants have the fleshy root systems. Some 

 fleshy roots, such as the (sweet potato and dahlia, resemble tubers 

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