112 



Elementary Principles of Agriculture 



drop of food at the base of the ovary. When the bee 

 enters the flower to gather bee-bread (pollen) and the 

 honey, or nectar, at base of pistil, some of the pollen is 

 lodged on its head and legs and body. When it enters 

 the next flower, some of this pollen is caught by the 



stigma. (Fig. 55.) Many 

 kinds of flowers are solely 

 dependent on the going and 

 coming of insects to bring 

 about pollination and, there- 

 fore, the formation of fruit 

 and seed. We used to think 

 that flowers had their gor- 

 geous colors to please man's 

 fancy. We now know that it 

 is to attract the lowly in- 

 sects. Usually, night-bloom- 

 ing flowers are white and 

 give off their odors more 

 strongly at night (study the 

 tuberoses, rain lilies, night- 

 blooming cereus, moon-flow- 

 / ers, etc.), in order to attract 

 the night-flying moths. Blue 

 and red flowers are day 

 bloomers. 



168. Growth of the Pollen 

 Grains. The pollen grain is 

 a very small body, consisting of one or two cells. 

 When it is deposited on the moist stigma, it begins to 

 grow a slender tube (pollen-tube) down into the ovary. 

 169. Fertilization. The pollen-tube produces a small 

 cell that contains a nucleus that passes into and unites 



Fig. 56. Diagrammatic section of 

 ovary and ovule at time of fertili- 

 zation, m, micropyle; k, egg cell; 

 The pollen tube is shown down 

 through the style, between the 

 walls of the ovary and ovule, to 

 the egg cell, k, of the embryo sac. 



