218 



EXPERIMENTAL GENERAL SCIENCE 



When the stamens are borne on different parts of the same 

 plant the species are moncecious. Most plants, however, 

 have stamens and carpels in the same flower. 



184. Species and Higher Groups. The most careless ob- 

 server must have noticed that the differences that separate one 

 living thing from another are not always of the same magni- 

 tude. There is a greater difference between a cow and a 

 cabbage than there is between a turnip and a cabbage, or be- 

 tween a cow and a sheep. If we continue to narrow our com- 

 parisons, we soon come to groups in which the individuals 



FIG. 83. A typical flower with all 

 of the floral organs. 



Q \> 



FIG. 84. Compound carpels. 



resemble one another more than they resemble anything else. 

 Such a group is called a species. All garden sunflowers, or 

 white clovers, or English sparrows, belong to a single species. 

 We are well aware, however, that there are other kinds of 

 sunflowers, clovers, and sparrows which resemble our typical 

 species more than they do other plants or animals. It is, 

 therefore, possible to arrange species which resemble one 

 another into larger groups called genera (singular genus}. In 

 the same way we may assemble the genera into families and 

 the families into orders. For instance, there are a number of 



