GENEEAL PEINCIPLES OP CLASSIFICATION 7 



1. Sub-kingdoms or Divisions. 

 Sub-divisions. 

 2. Classes. 



Sub-classes. 

 Series. 



Cohorts or Alliances. 

 3. Oedees. 



Sub-orders. 

 Tribes. 



Sub-tribes. 



4. G-ENEHA. 



Sub-genera. 



Sections. 



5. Species. 



Varieties. 

 Races. 



Section 2. — Characters, Nomenclature, Abbreviations, 

 AND Symbols. 



Descriptivb Botany is the art of describing plants in tech- 

 nical language, so that they may be readily recognised when met 

 with by those to whom they were previously unknown, who pos- 

 sess a knowledge of the technical names of the different parts 

 and organs of plants and of their various modifications. This 

 subject is too extensive to be treated of here ; reference must 

 be made to special treatises for this purpose ; but it is necessary 

 for us to refer briefly to the Characters, Nomenclature, Abbre- 

 viations, and Symbols of Plants. 



1. Characters. — By the term ' character,' we mean a list of 

 all the points by which any particular ■wariei?/, species, sub-genus, 

 genus, sub-tribe, tribe, sub-order, order, sub-class, or class, &c., is 

 distinguished frora another. We have also two kinds of characters, 

 which are called respectively essentia I and natural. By an essen- 

 tial character, we understand an enumeration of those points 

 only, by which any division of plants may be distinguished from 

 others of the same nature ; such may be also called diagnostic 

 characters. A natural character, on the other hand, is a com- 

 plete description of a given species, genus, order, class, &c., 

 including an account of every organ from the root upwards, 

 through the stem, leaves, flowers, fruit, and seed. Such cha- 

 racters are necessarily of great length, and are not required for 

 general diagnosis, although of great value when a complete 



