IOO Principles of Plant Culture. 
other crops, intended for coarse fodder, is much reduced by 
permitting the seed to ripen before cutting. 
162. The Ripening of Fruits. Green fruits assist the 
leaves in assimilation 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 be- 
come sour from the production of acids. These disappear 
in part at a later stage, while sugar is notably increased. 
Some fruits, as the strawberry and peach, increase rapidly 
in size during the ripening period, provided the water supply 
is sufficient. 
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. A 
Section XIII. THE GATHERING AND STORING OF SEEDS 
163. The Stage of Maturity at which Seeds will 
Germinate varies greatly in different plants, and bears no 
direct relation to the time at which the seeds are set free 
from the parent plant. Seeds of the tomato will germinate 
when the fruit is little more than half grown, and those 
of the pea will germinate when fit for table use. On the 
other hand, seeds of the thorn (Crategus) and juniper 
rarely germinate until the second spring after their produc- 
tion. Seeds of many annual and biennial plants, as the 
cereals, cabbage, etc., may germinate as soon as set free by 
the parent plant, but those of many annual weeds, and of 
most trees and shrubs, will not germinate until some months 
afterward. 
