CLASSIFICATION AND NOMENCLATURE 171 



belong to one and the same species, but are classed 

 as two different varieties of it. For the seeds of 

 sona-moog are golden-yellow, leaves pale-green, and 

 pods reflexed ; whereas the seeds of krishna-moog are 

 black, leaves darker green, and pods spreading hori- 

 zontally. These differences are permanent, but not 

 important enough to be considered as specific. A 

 VARIETY differs from a species in the fact that a 

 change in its environment, and in other external 

 conditions of growth, tends to make it revert to the 

 parent species from which it has sprung. 



On the same principle of resemblances and differ- 

 ences, the genera that resemble one another more 

 closely than they resemble other genera are thrown 

 into groups known as Natural Orders. Similarly, 

 Orders are grouped into Sub-classes, Sub-classes into 

 Divisions, Divisions into Sub-kingdoms, till we arrive 

 at the whole collection of plants known as the Vege- 

 table Kingdom. When a particular group is very 

 large, it has often to be subdivided into intermediate 

 groups, as Sub-classes into Cohorts, Orders into Sub- 

 orders, Genera into Sub-genera, and so on. 



Nomenclature. — The naming of plants is a part 

 of classification, and as such it demands our attention. 

 Every species of plants has a name by which it is dis- 

 tinguished from all other species. Thus ata species 

 is named Anona squamosa, dhutura species is named 

 Datura Stramonium, and aloo species is named 

 Solanum tuberosum^ &c. The name of each plant 

 thus consists of two parts; the first part indicates the 

 genus to which the plant belongs, and the second 

 part indicates the species to which the plant belongs. 

 Thus it will be seen that the three plants named above 

 not only belong to three different species, but also to 

 three different genera. The first part of the name is 



