134 



FERTILIZATION AND POLLINATION 



receptive. The stigma may remain receptive for several hours 

 or even days, depending on the kind of plant, the weather, 

 and how soon pollen is received. When fertilization takes 

 place, the stigma 

 dies. Note the dried 



222. Flower of hollyhock; proterandrous. See Fig. 223. 



end of the "silk" of corn. Observe, also, how soon the petals 

 wither after the stigma has received pollen. 



278. Pollination. The transfer of the pollen from anther 

 to stigma is known as pollination. The pollen may fall of its 

 own weight on the adjacent stigma, or it may be carried 

 from flower to flower by wind, insects or other agents. There 

 may be self-pollination, close-pollination or cross-pollination. 



In self-pollination, 

 the pollen that falls 

 on the pistil is de- 

 rived from the same 

 flower. In close- 

 pollination, the pol- 

 len may be derived 

 from different flowers 

 on the same plant. 

 In cross-pollination, 

 the pollen is derived 



223. Older flower of f?f / * a viv 



hollyhock. Ml from flowers on differ- 



