ORGANS OF REPRODUCTION. 



53 



to be fertilized, soon after wliich the calyx, corolla, and 

 stamens generally wither and fall away. The ovary at 

 this time contains one or more soft granular bodies, 

 called ovules, being embryo seeds ; shortly after this 

 the ovary begins to enlarge, increasiag in size until it 

 arrives at maturity, when the plant is said to be in 

 seed, or more properly in fruit, which is very various in 

 form and structure. 



In order to insure fertilization, nature is profuse in 

 the supply of pollen, the quantity used being infinitely 

 small to that wasted. When corn and grass are in flower 

 it floats in the air, and is supposed to be the cause of 

 some diseases, especially " hay fever." In the Fir 

 family it is produced in abundance, and in fir forest coun- 

 tries is carried to a great distance, even to hundreds^ 

 of miles, and on falling to the ground forms a yellow j 

 crust like sulphur, which has given rise to the idea 

 that it had rained brimstone ; such may be seen near 

 fir trees in this country. 



From what has been stated, it may be presumed that 

 the proximity of the stamens and pistil or pistils in her- 

 maphrodite flowers is for the purpose of insuring 

 fertilization. Mr. Darwin has, however, shown that such 

 is not the case in all flowers ; experiments with the 

 Primula, Lythrum, Linum, and passion-flower prove 

 that the pollen is inert on the pistil of its own flower, 

 but efi'ective in fertilizing the pistil of other flowers. In 

 many plants, such as the grass of Parnassus, the stamens 

 and pistils are not perfect at the same time, the pollen 

 being shed long before the pistil is perfect ; in others, 

 such as banana, it is the contrary, the pistiliferous 

 flowers being early developed, and the ovary swelling 

 long before the male flowers are free of their enclosing 



