118 PLANT LIFE ON THE FARM. 



Plants cultivated for their roots, etc Under this 

 head are included such crops as turnips, kohl rabi, 

 potatoes, heet-root, mangels, and onions. In all of these 

 the cellular tissue largely preponderates over the fihrous. 

 The cells are filled with water and with various substances, 

 such as starch and other secretions. In the economy of 

 the plant these secretions are manufactured in one season, 

 stored in the cells, and used up in the next season for the 

 production of leaves, flowers, and seeds. The work of the 

 leaves then of these plants differs to some extent according 

 to season ; those of the first year work to build up the plant 

 and to store up the secretions in the " roots " or tubers, 

 while the office of those produced in the succeeding year is 

 more particularly to form and nourish the flower, fruit, and 

 seed, and to secure the accumulation of nutritive matter in 

 the seed. Unless the farmer requires the plants to seed, he 

 uses up the roots for his own purposes before any demand 

 is made upon the plant for flower and fruit building. 



Speaking generally, the indications furnished by the 

 nature of the plants, point to the necessity or desirability 

 of a light, rich, friable soil for their culture, one which will 

 permit of ready root range, and which, while supplying 

 ample food, shall not harbour stagnant water. Rapid 

 growth and vigorous leaf-action are also indicated, as, when 

 these are secured, the cellular portions required grow in 

 proportion faster and more freely than the fibrous portions, 

 and the requisite secretions are stored the more readily in 

 the roots. To ensure this rapid growth, more essential in 

 an annual crop like potatoes than in those whose growth 

 occupies part of two seasons, a warm aspect and a well- 

 drained soil are essential, while to ensure the formation of 

 the secretions which render the plant valuable, free expo- 



