440 



How Afiimals and Vlants Reproduce unit viii 



Fig. 388 The corn plant has two kinds of flowers. One kind has only stamens. These 

 are f on/id at the top of the plant in the tassel (left). The ear of corn (right) is a 

 group of flowers with pistils only. They are wrapped in the husks; only the ends of 

 the pistils stick out. (u. s. department of agriculture) 



reproduction. For this reason the stamens 

 and pistils are often called essential or- 

 gans. They are essential to reproduction 

 because they contain the gametes. The 

 other flower parts, the sepals and petals, 

 may help indirectly, but they are not 

 necessary. Sometimes they are much re- 

 duced in size or even lacking altogether. 

 Certain species, such as corn and the 

 willows, have stamens and pistils in sepa- 

 rate flowers instead of in the same flower 

 as they are in the lily or tulip. A flower 

 that has stamens but no pistil is called a 

 stainlnate flower. A ■pistillate flower is 

 one that has one or more pistils but no 

 stamens. In corn the two kinds of flowers 

 occur on the same plant. Among willows, 

 the staminate and pistillate flowers are 

 found on different trees. 



How the pistil is essential. A pistil con- 

 sists usually of three parts: a top that is 

 often flattened and broad called the 

 stig7/ia; a stem or neck below the stigma 

 called the style; and a large thickened 

 lowest part, the ovary. Examine Figure 

 387 to see these three parts. In tulips the 

 style is very short. If you cut into the 

 ovary, you will find ovides (oh'vules) 

 within. The word ovule means little t^^ 

 but this word is badly chosen, for an 

 ovule is not an tgg at all. In some kinds 

 of flowers the ovar>^ contains only one 

 ovule; in others there are hundreds of 

 tiny ovules crowded into the ovary. 

 Ovules may be so small that one needs a 

 microscope to see them but in many 

 flowers thev can be seen with the naked 

 eye if you cut open the ovary. When 



