CLASSIFICATION OF ANIMALS AND PLANTS 135 



Botanical Gardens. Many names of species are of geographi- 

 cal origin; e.g., canadensis, virginica, americanus, europea, 

 etc. 



The student of animals and plants should remember that 

 a large number of names are no longer descriptive. For 

 example, Claytonia virginica is found in many states besides 

 Virginia ; and many species originally named vulgaris, mean- 

 ing common, have become relatively uncommon. However, 

 this does not interfere with the use of the names as definite 

 designations for particular kinds of animals and plants. 

 There are many names in the human families which do not 

 correctly describe their bearers, e.g., Mr. White, a negro; 

 and Mr. Black, a white man ; but these meaningless names 

 serve to mark the individuals. 



124. Genera and Species. In many earlier lessons of 

 this book the word species has been used in its popular sense, 

 meaning a kind of animal or plant. It is now time for a 

 more accurate definition of the word as used in biology. 



The pansy, Viola tricolor, has been referred to as a species 

 of violet. One might buy pansy seed from hundreds of 

 dealers in seeds, and from these seeds grow thousands of in- 

 dividual plants which by the form of stem and leaves, and 

 by the form and colors of the flowers, would be recognized 

 by any gardener as pansy plants. In short, pansies con- 

 stitute a species, a group of closely similar individuals. 



Now, many specimens of violet plants producing yellow, 

 blue, and white flowers might be collected ; and comparison 

 would show that the individual plants with yellow flowers are 

 closely similar, but differ from those with white and blue flowers 

 and from pansies. Hence the similar individual plants with 

 yellow flowers would be named as a species distinct from the 

 others. Note, however, that all parts of the plants must be 

 compared, and not color alone, as the above illustration might 

 suggest. For example, a blue violet with rounded leaves 

 would be considered one species, and a blue violet with lance- 



