276 THE KINDS OF PLANTS 



species. We make species merely to enable us to talk 

 and to write about plants : we must have names to call 

 them by. The different kinds of plants are the results 

 of evolution. Probably none of them were created in the 

 beginning as we now find them. 



NAMES OF SPECIES.— For one hundred and fifty years 

 (since Linn»us published his "Species Plantarum " in 

 1753), species have been known by two names, the generic 

 and the specific. The generic name is the name of the 

 genus or group to which the plant belongs: it corresponds 

 to a surname. The specific name belongs only to the 

 particular species or kind : it corresponds to a given or 

 Christian name. Both names are necessary, however, to 

 designate the species. Thus Querctis is the generic name 

 of all the oaks. Quercus alba is one of the oaks (the 

 white oak), Q. virens (the live oak) another. All maples 

 belong to the genus Acer, and all elders to Satnbucus. 

 The same specific name may be used in any genus, as the 

 same Christian name may be used in any family. Thus, 

 there is a Quercus nigra, Sambncus nigra, Acer nigrum, 

 "niger" meaning black. 



By common consent, the oldest proper name of any 

 species must stand. If a species happens to have been 

 named and described twice, for example, the first name, if 

 in the proper genus, must hold; the later name becomes a 

 synonym. It sometimes happens that the same specific 

 name has been given to different plants of the same genus. 

 Of course this name can be allowed to stand for only one 

 species, and the other species must receive another name. 

 In order to avoid confusion of this and other kinds, it is 

 customary to write the author's name with the species- 

 name which he makes. Thus, if Gray describes a new 

 Anemone, his name is written after the plant name: Ane- 

 mone cylindrica, Gray. The author's name thus becomes 

 an index to the history of the species -name. 



