2O Leading Principles of the Growth of Trees. 



the calyx. The essential parts of the flowers are the stamens and 

 pistils. Fig. 7 represents an enlarged flower of the cherry, cut 



through the middle, showing the 

 small calyx, the large corolla, the 

 many stamens, and the single 

 pistil. Fig. 8 is a magnified 

 flower of the purslane, showing 

 several pistils. The head of the 

 stamen (b, Fig. 9) is called the 

 anther. It contains a powder 

 called pollen, which is discharged 

 Fig. 7. by the bursting of the anther, 



Flower of the cherry. the pollen being the fertilizing 



matter, essential to the produc- 

 tion and growth of the new seed. The thread-like stalk of the 

 stamen (a) is called the filament. The pistil (Fig. 10) consists of 

 the stigma, c, at the top ; the style, b, its support ; and the ovary, a, 



Fig. 8. 

 Purslane flower. 



Fig. 9. 

 Stamen. 



or future seed-vessel. The ovules, d, are the rudimentary seeds. 

 The pollen of the stamens falls on the stigma, and the ovules are 

 fertilized or impregnated, and become seeds. 



Sometimes the stamens and pistils are in different flowers, on dif- 

 ferent parts of the plant. A familiar instance occurs in Indian-corn, 

 the "silk" being the pistils, and unless these are impregnated by the 

 pollen of the anthers at the top, no grains of corn will be produced. 



Sometimes the staminate and pistillate flowers are not only sepa- 

 rate, but are on distinct plants, as the Buckthorn and Hemp. The 

 pistillate flowers are said to be fertile, and the staminate sterile, and 

 both must be planted near each other in order to obtain fruit or 

 seed. 



