152 



PLANT BIOLOGY 



some kinds of plants, with the remains of the old cleistog- 

 amous flower still adhering to the root. Cleistogamous 

 flowers usually appear after the showy flowers have 



FIG. 206. PODS OF PEANUTS RIPENING UNDERGROUND. 



passed. They seem to insure a crop of seed by a 

 method that expends little of the plant's energy. The 

 pupil will be interested to work out the fruiting of the pea- 

 nut (Fig. 206). 

 Unbaked fresh 

 peanuts grow 

 readily and can 

 easily be raised 

 in the North in 

 a warm sandy 

 garden. 



SUGGESTIONS. 

 152. Not all the 

 flowers produce 

 seeds. Note that 

 an apple tree may 

 FIG. 307. STRUGGLE FOR EXISTENCE AMONG THE bloom very full, 

 APPLE FLOWERS. but that only rela- 



tively few apples 



may result (Fig. 207). More pollen is produced than is needed to 

 fertilize the flowers ; this increases the chances that sufficient 



