64 Principles of Plant Culture. 



84. The Storage of Reserve Food. In healthy plants, 

 food is usually prepared faster .than it is consumed 

 by growth. The surplus may be in the form of starch, 

 as in the potato (Fig. 16), wheat and sago; sugar, as 

 in the sugar cane, sugar maple and beet; or oil, as in 

 cotton seed, flax seed and rape. Aside from the seeds, 

 which are always stocked with reserve food, certain 

 plants living more than one year as the potato, beet, 

 onion, kohl-rabi, etc., have special accumulations of food 

 in certain parts, and the parts of plants that contain 

 such reserve food are most valuable as food for man or 

 animals. The proportion of starch stored in potato 

 tubers is not constant, hence the food value of different 

 samples of potatoes may vary greatly. In woody plants, 

 the surplus food is more evenly distributed through the 

 different parts, though the older leaf-bearing wood is 

 usually best supplied. 



85. Plants Use their Reserve Food in the production 

 of flowers and seeds (134 A), and in repairing damages, 

 as the healing of wounds (72), or the replacement 

 of leaves destroyed by insects or otherwise. Annual 

 plants (337) expend all their reserve food in flower 

 and seed production and then perish as soon as the seed 

 is ripe. Biennial plants devote the first season of their 

 life to storing an abundant food supply, which is ex- 

 pended in flower and seed production the second year. 

 Our seed crops, as oats, corn, peas and beans, are mostly 

 annuals; our vegetables other than seeds, as beets, cab- 

 bage, parsnips and celery, are mostly biennials. Peren- 

 nial plants, in normal condition, expend only a part of 

 their reserve food in any one season for the production 



