SECT. II. TAXONOMY AND PHYTOGRAPHY. 153 



ready enumerated ; whilst in Polygamia the orders 

 are characterised by the flowers being monoecious, 

 dioecious, or trioecious. 



There is no connection betweeu the nomenclature 

 of the orders of the class Cryptogamia, and the charac- 

 ters of the plants they contain ; but some of them are 

 familiar to most persons, as the ferns (Filices), mosses 

 (Musci), seaweeds (Algae), mushrooms (Fungi). 



(138. bis.) Application of the Linntean System. Not- 

 withstanding the apparent great simplicity of this 

 system, there are many anomalous cases to which it 

 cannot be directly applied. In order to meet these, 

 Linnaeus made use of an expedient by which such 

 species as do not strictly belong to the class and 

 order under which their genus is arranged, may still be 

 ascertained. Their names are placed in Italics at the end 

 of the order to which they really belong, and in which 

 they would naturally be sought for ; so that the student, 

 who has not been able to detect them among the genera 

 there enumerated, may refer to the index, and search 

 among these anomalous cases. Thus, for example, the 

 genus Gentiana is classed under Pentandria Digynia ; 

 but Gentiana campestris has generally only four sta- 

 mens, and would be sought for under Tetrandria Di- 

 gynia. Not being found among the genera there 

 enumerated, it must be one of the few anomalous 

 species, whose names are mentioned ; and these must 

 be all referred to, before it can be determined which 

 of them it may be. The very unequal distribution 

 of the classes is another inconvenience in this system. 

 The great bulk of plants are included in about one 

 half of them, whilst the others contain comparatively 

 few. If, however, attention be paid to the general 

 form of the flowers, the relationship which usually 

 subsists between the divisions of the perianth and the 

 number of the stamens, in such as have a regular 

 corolla, and a few other particulars, the knowledge of 

 which a little practice alone can bestow, these diffi- 

 culties are soon greatly diminished, and many large na- 



