CLASSIFICATION AND NOMENCLATURE 169 



The key-note of classification is the conception of 

 what constitutes a species and what constitutes a 

 GENUS. The term species is applied to a collection 

 of individual plants which resemble one another in all 

 the important characters of their vegetative and repro- 

 ductive organs, and are therefore supposed to be 

 descended from a common ancestor. Thus, for ex- 

 ample, take the ata (Anona squamosa) plant. In- 

 dividual ata plants may differ from one another in 

 unimportant characters, such as the size of the plant, 

 the size of the fruit, &c. , but they resemble one an- 

 other in all important characters, such as general 

 appearance, the form, nature, and arrangement of 

 leaves, and the structure of flowers, fruits, and seeds; 

 and ata seeds produce ata plants from generation to 

 generation. All ata plants in the world are therefore 

 supposed to have descended from a common ancestor. 

 Thus the entire collection of ata plants constitutes a 

 species, say the ata species. So all nona plants (A. 

 reticulata) constitute a second species, say the nona 

 species; all bat or Banyan trees {Ficus bengalensis) 

 constitute a third species, say the bat species ; all 

 aswathwa or Peepul {F. religiosa) trees a fourth 

 species, say the aswathwa species: and all dumur 

 plants {F. hispida) a fifth species, say the dumur 

 species. 



Now of these five species, ata and nona species of 

 plants resemble one another more closely than they 

 resemble the other three species. Thus ata and nona 

 species of plants resemble one other in the structure 

 of their reproductive organs, and differ completely 

 from the other three species in the same respects. 

 These two species are therefore thrown into one 

 group, and that group is named a genus. Thus a 

 genus may be defined as a collection of species which 



