NOMENCLATURE AND SYMBOLS. 341 



the purpose of diagnosis. The essential characters of genera, when in 

 Latin, are put in the nominative case, while those of species are in the 

 ablative. 



712. Nomenclature. The names of genera are variously derived, 

 from the. structure or qualities of the group, from the name of some 

 eminent botanist, &c. ; while specific names have reference also to the 

 country where the plant is found, the locality in which it grows, the 

 form of the leaves, root, stem, or the colour of the flowers, &c. When 

 a species is named in honour of its discoverer or describer, his name is 

 put in the genitive, as Carex Vahlii, or the Carex detected by Vahl; 

 but if it is merely in compliment to a botanist, his name is added in 

 an adjective form, as Jungermannia Doniana, or a Jungermannia named 

 in honour of Don, as a botanist. Sometimes two nouns are united in 

 a specific name, as Dictamnus Fraxinella. In such cases, the specific 

 name is often an old generic one, has a capital letter prefixed, and 

 does not necessarily agree in gender with the name of the genus. The 

 name of the orders in what is called the natural system, are derived 

 from one of the typical genera included under them. 



713. Abbreviations and Symbols. It is of great importance that 

 correct descriptions should be given of species, for without them it is 

 impossible to form the groups accurately. The difficulties of the 

 taxonomist are often greatly increased by imperfect and careless 

 descriptions. Valuable directions are given in Lindley's Introduction 

 to Botany, as to the proper method of describing plants. There are 

 certain abbreviations in constant use among botanists, which it may 

 be of importance to notice here. The authorities for genera and 

 species are given by adding the abbreviated name of the botanist who 

 described them. Thus, Veronica L., is the genus Veronica as defined 

 by Linnaeus; Veronica arvensis L., is a certain species of Veronica, de- 

 fined by the same author; Oscytropis DC., is the genus as defined by 

 De Candolle. It is usual in descriptive works to give a list of the 

 authors, and the symbols for their names. The abbreviation v. s. sp., 

 means vidi siccam spontaneam, or that the author has seen a dried wild 

 specimen of the plant; v. s. c., means vidi siccam cultam, or that he 

 has seen a dried cultivated specimen; v. v. s., means vidi vivam spon- 

 taneam, or that he has seen a living wild specimen; while v. v. c., 

 means vidi vivam cultam, or that the author has seen a living cultivated 

 specimen. The asterisk prefixed to a name (* L.), indicates that there 

 is a good description at the reference given to the work; while the 

 dagger (fL.), implies some doubt or uncertainty. The point of admira- 

 tion (! DC.), marks that an authentic specimen has been seen, from 

 the author named; and the point of interrogation (?) indicates doubts 

 as to the correctness of genus, species, &c., according as it is placed 

 after the name of the one or other. , Q > > or A, annual ; <J , O Q , 

 0, or B, biennial; 1{, A, or P, perennial; \\ , 5, or Sh, shrub; 



