GENEEAL PEINCIPLES OF CLASSIFICATION 9 



of the genus. Thus, when a species is named after its discoverer 

 or describer, it is usually placed in the genitive case, as Viola 

 Mulilenhergii and V. NuttallU ; but when such names are merely 

 given in honour of botanists who have had nothing to do with 

 their discovery or description, the specific names are generally 

 put in the adjective form, as Carex Hookeriana, Veronica 

 Linclleyana : such a rule is, however, frequently departed from. 

 Sometimes the specific name is a noun, in which case it does 

 not necessarily agree with the genus in gender ; such specific 

 names are often old generic ones, as Dictamnus Fraxinclla, Bhus 

 Cotinus, Lythrum Salicaria, Rhus Coriaria, Diantlius Ar- 

 meria, Rhammis Frangula. In such cases the specific name 

 should begin with a capital letter ; a similar rule should also be 

 adopted when it is derived from a person ; but in all other 

 instances it is better that the specific name should begin with a 

 small letter. The specific name was called by Linnaeus the 

 trivial name ; thus, in the particular kind of Violet called Viola 

 j)alustris, Viola is the generic, and palustris the specific or 

 trivial name. 



b. Genera. — The names of the genera are substantives, in 

 accordance with the rule laid down by Linnaeus as follows : — 

 Every species shall have a particular name, compounded of a 

 substantive and an adjective, whereof the former indicates the 

 genus, and the latter the species. This has already' been re- 

 ferred to under the head of Species. The names of the genera 

 are derived in various ways : thus, either from the name of some 

 eminent botanist, as Linnaea after Linnaeus, Smithia after Smith, 

 Hookeria after Hooker, Jussiae after Jussieu, Tournefortia after 

 Tournefort, Lindle^-ana after Lindley ; or from some peculiarity 

 of structure or habit of the plants comprised in them, and from 

 various other circumstances. Thus, Crassula is derived from 

 the genus comprising plants with succulent or thickened leaves ; 

 Sagittaria, from its arrow-shaped leaves ; ^Ire/mria, from grow- 

 ing in sand}^ places ; Lithos2)ermum, from its fruits (which were 

 formerly regarded as seeds) having a stony hardness ; Camj^a- 

 nula, from its corolla being in the form of a bell ; Lactuca, from 

 its milky juice ; and so on. Others, again, have derived their 

 generic names from supposed medicinal properties, such as Sci'o- 

 phularia, from its former use in scrofula ; Pulmonaria, from its 

 employment in pulmonary disease, &c. 



c. Orders. — The names of the orders in the Artificial 

 System of Linnaeus are chiefly derived from the various charac- 

 ters of the gynoecium and fruit. Those of Natm'al Systems are 



