PLANTS 319 



carpel (Figure 278) ; a compound pistil has more than 



one carpel. In the base of the pistil is a bulblike seed 



case called the ovary. This contains the 



ovules or eggs. Above the ovary is a 



slender stem called the style, and at the 



end of the style is a sticky surface called 



the stigma. 



Pollination. In order that seeds may 



be produced, it is necessary that pollen 



from the anthers lodge on the stigma. 



This may happen in several ways. The 



anthers of some flowers burst when ripe FIG. 275. Calyx 



and scatter the pollen on the stigma. The and Corolla. 



wind may blow the pollen so that it falls on the stigma. 



Insects flying from one flower to another often carry 

 pollen from the anthers of one flower to 

 the stigma of another. This is cross- 

 pollination. 



Fertilization. Each pollen grain con- 

 sists of a particular cell called the sperm 

 cell. When the pollen grains fall on the 

 stigma, they -are held by the sticky sur- 

 face. They immediately begin to grow, 

 forming tubelike roots which grow down- 

 ward through the stigma and the style 

 into the ovary, where they pierce the 

 ovule and reach the egg cell. The sperm 

 cell of the pollen meets the egg cell of 

 FIG 276 Three tne OVU ^ Q an d they unite to form a 



stamens with Differ- single cell, which grows and forms an 



ent Forms of Anther. , , /TV rM-rrv\ rrn 



embryo plant (Figure 279). The parent 

 plant stores food around this plant, with the result 

 that fruits and seeds are formed. The fruits are simply 



