CHAPTER IV 

 Hybridization of Plants 



Several years ago there was much discussion of the use of the 

 words hybrid and cross. The writers now use these words inter- 

 changeably. A hybrid is a cross between two plants which differ 

 in one or more characteristics. As all plants differ, a hybrid is the 

 result of any cross. Formerly, hybridity meant weakness, but now 

 we have come to see that hybrids often surpass the parents in 

 vigor and quality. 



In order to cross plants successfully one must intimately study 

 their structure. We must distinguish the male and female parts 

 and their relative time of ripening. It is true that all flowers are 

 essentially the same. A perfect flower has both male and female 

 parts in the same flower. The male portions are the stamens; they 

 bear the pollen. The female portion is known as the pistil ; it usually 

 has a sticky or feathery head so that pollen once lodging there may 

 remain. At the base of the pistil is the ovary, or more properly 

 called the ovulary; its function is to bear the seeds. Besides these 

 essential parts of the flower there may also be found showy petals 

 and leaf -like sepals, but they are non-essentials. (See Fig. 8). 



In the Rose, there are many stamens prominently filling the 

 center of the flower; tucked in among them at the very center is 

 the small bunch of pistils. To form seed it is necessary for pollen 

 grains to fall on the pistils. Each ovule in the ovary is waiting for 

 a pollen grain in order that it may produce a seed. In the Poppy 

 and Orchid capsules are thousands of seeds, each of which resulted 

 from the growth of a pollen grain placed upon the pistil. In Corn 

 the stamens are the tassels, the pistils are the silks. Any silk which 

 fails to receive a pollen grain also fails to produce a kernel of corn; 

 a blank in the ear results. 



There is a large group of Daisy like flowers, for example, the 

 Lettuce, Zinnia, China Aster and Chrysanthemum. In these plants 

 what appears to be a flower is really a bunch of small flowers. 

 Flowers in the outer row are usually larger and more showy, while 



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