164 



Introduction to Botany. 



reproductive cell is much larger than the other, is stored 

 with food materials, and is stationary, while the smaller re- 

 productive cell is motile, seeks 

 the larger cell, and fuses with 

 it. The larger cell may there- 

 fore be designated the female 

 reproductive cell or egg, and 

 the smaller cell the male repro- 

 ductive cell or sperm. 



119. Functions and Relation- 

 ships of Floral Structures. — 

 The essential parts of a flower 

 consist of the sperms and the 

 eggs, and the organs which 

 bear and protect them. Figure 

 87 is a diagrammatic represen- 

 tation of a typical flower. At 

 ^ is a sepal, one of the external 

 members of the flower, which 

 taken collectively constitute 

 _, . . ^ J .,■ the calyx. The calyx enwraps 



Reproduction in OecLogo7iium cilia- -^ ^ ^ 



turn. I, a, an oogonium in which is the Other parts of the flower 



borne the large egg cell ; i, an an- j^ ^^^ ^^^ ^^^ j^^^ ^^^^ ^^^^ 

 thendium in which the sperm cell o 



occurs; 2, showing the sperm cell degree of protection, and some- 

 after it has entered the oogonium , . -j. • i. • -l*.! 1 j j 



andis fusing with the egg; 3 show- timcs it IS brightly colored and 

 ing the protoplasts in two cells of an helps to make the flower con- 



Oedogonium filament ready to . t, • 



emerge and become asexual swarm SpiCUOUS. It IS not nCCCSSary 



spores; 4, an asexual swarm spore, to the production of SCCds, and 

 After Pringsheim. 



IS sometimes wanting. 



At c is a petal. The petals constitute the corolla ; they 



are usually white or brightly colored ; in the bud they 



enwrap the inner members and thus help to protect them, 



and in the open flower they are advertisements to insects, 



3 



\ 

 Fig. 86. 



