128 CLASSIFICATION. [chap. 



again (to which substantive names are applied for conve- 

 nience) under Divisions, the divisions under Sub-classes and 

 Classes, as we have already pointed out. Thus the charac- 

 ters of a Class are common not only to its Sub-classes and 

 Divisions, but to the Natural Orders, Genera, and Species 

 included in that Class. It follows, therefore, that the 

 characters of a Class must be more constant and more 

 general than those of a Sub-class or Division, those of a 

 Division than those of a Natural Order, of a Natural Order 

 than those of a Genus, and of a Genus than of the Species 

 which it includes. 



5. Botanists distinguish as varieties groups of individuals 

 of a species which are marked in common by some trivial 

 character, subordinate in importance to the characters which 

 are used to separate species. Thus we may have orange and 

 purple varieties of the same species of Zinnia, awnless and 

 awned varieties of the same species of Rice, &c. ; the colour 

 of the flower of the Zinnia and the presence or absence of 

 an awn in Rice being characters too liable to variation to 

 serve to separate species. 



6. The following pages are chiefly devoted to an examina- 

 tion of representative Types of most of the Natural Orders 

 of flowering plants native in India. 



I must here emphatically impress upon the beginner, that 

 it is useless attempting to study this portion of the book 

 without a constant reference to living specimens, without 

 which any information he may acquire from it will be com- 

 paratively unavailable when tested in the field. Numerous 

 references are given to plants which show peculiar departures 

 from the several Types. Specimens of these ought to be 

 procured whenever it is possible, and dried for further use in 

 the way described in the last chapter of this book. When 

 a preparation can be preserved without pressing it between 



