106 Principles of Plant Culture. 



grain has been threshed, is comparatively small, and 

 that of grass and other crops intended for coarse fodder 

 is much reduced by permitting the seed to ripen be- 

 fore cutting. 



161. The Ripening of Fruits. Green fruits assist the 

 leaves in food preparation to some extent, but as they 

 begin to ripen, the process is reversed. Carbonic acid 

 and water are then given off, while oxygen is absorbed. 

 Fruits first become sour from the production of acids 

 which disappear in part at a later stage, while sugar is 

 notably increased. Ripening is favored by warmth and 

 in some fruits by light. 



Some fruits, as the strawberry and peach, increase 

 rapidly in size during the ripening period, provided 

 the water supply is sufficient. 



Color is not always an index of maturity. Blackber- 

 ries, currants and certain other fruits improve in edible 

 quality for some time after assuming their mature color. 



Most fruits that have attained nearly normal size 

 ripen to a degree when detached from the parent plant. 

 Pears are usually improved in quality if picked before 

 maturity and ripened in-doors. The grape, however, 

 fails to develop its sugar if prematurely picked. 



After a certain stage of maturity is reached, all vital 

 processes in the pulpy part of the fruit cease, and dis- 

 organization (decay) begins, unless prevented by a pre- 

 servative process. 



SECTION XII. THE GATHERING AND STORING OF SEEDS. 



162. The Stage of Maturity at which Seeds will 

 Germinate varies greatly in different plants and bears 



