400 SYSTEMATIC BOTANY, OR 



Hen slow has taken as an illustration of these different divi- 

 sions Anthyllis Vulneraria, thus : — 



1. Class ..... Dicotyledones. 



Sub-class Calycifiorce. 



2. Order ..... LeguminoscB. 



Sub-order PapilionacecB. 



Tribe Lotece. 



Sub-tribe Genistece. 



3. Genus Anthyllis. 



Sub-genus or Section . . . Vulneraria. 



4. Species ..... Vulneraria. 



Variety Dillenii. 



Race ...... Floribus coccineis. 



Variation Foliis hirsutissimis. 



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

 the points by which any particular variety, species, genus, sub- 

 order, order, sub-class, or class, is distinguished from another. 

 We have also two kinds of characters, which are called, re- 

 spectively, essential and natural. By an essential 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 complete description 

 of a given species, genus, order, or class, including an account 

 of every organ from the root upwards, tlu'ough the stem, leaves, 

 flowers, fruit, and seed. Such characters are necessarily of 

 great length, and are not required for general diagnosis, al- 

 though of great value Avhen a complete history of a plant or 

 group is required. Those characters again, which refer to a 

 species, are called specific, and are taken generally from all the 

 organs of the plant, and relate chiefly to their foi-m, surface, 

 division, colour, dimension, and duration, or to characters of a 

 superficial nature, and witliout reference to internal structurt 

 The characters of a genus are called generic, and are taken from 

 the organs of reproduction. The characters of an order are 

 termed ordinal, and are derived from the general structure of 

 the plants in such groups, more especially of tlic organs of re- 

 production i while the characters of a class, as already mentioned, 

 are derived from certain important anatomical peculiarities 

 which the plants of such divisions cxliibit. The essential cha- 

 racter of a genus, when indicated in Latin, is jiut in the 

 nominative case, while that of a species is ])laced in the ablative. 



Nomenclature. — The names of the classes are derived from 

 some important and permanent characters which they possess, 

 relating either to their structure or mode of development. 

 Such names vary, however, according to the views of difl'erent 

 systematic botanists. Those more commonly used in this 



