128 GENERAL BIOLOGY 



of course, at night. During the day the sugar is 

 usually converted into starch and stored up in the 

 leaves as such. During the night, however, this 

 excess is converted again into sugar and carried 

 away to nourish the plant elsewhere. As in animals, 

 various parts of the plant may serve as storehouses. 

 Accumulations of food are usually found in seeds, 

 where their presence is of manifest advantage to the 

 developing plant. Under the influence of certain 

 fungi the underground stems of certain plants (e.g. 

 the potato) thicken up and accumulate starch. 

 Such accumulations of " reserve " food may not 

 always be starch. They may be sugar (sugar beet) 

 or fat (cotton seed) . 



Some plants, including the whole group of fungi 

 (molds, etc.), draw their food supply from other 

 plants or animals. As they get their food at second- 

 hand, already elaborated, they lack or have lost the 

 special structures by means of which other plants 

 manufacture their own food. 



