GEXERAL PEIXCIPLES OF CLASSIFICATION. 393 



is included in any particular oKler, and which may be regarded 

 as the type of that order. Thus the genus Eanunculus gives the 

 name Eanuncidacece to the order to which it belongs; the genera 

 Papaver, Malva, Hypericum, Geranium, Rosa, Lilium, Orchis, 

 and Iris, in like manner, give names respectively to the orders 

 PapavcracecB, MalvacecB, Hypericacecs , Gtraniacece, Bosacece, Li- 

 liacea, OrchidacccB, and Irklacea. At other times, the names of 

 the orders are derived from some characteristic feature which the 

 plants included in them present. Thus the order CrucifercB 

 is so named, because the species it includes have the four petals 

 of their flowers arranged in a cross-l^ke form ; the order Legti- 

 minoscB comprises plants whose fruit is a legume ; the Umbel- 

 lifercB are umbel-bearing plants ; the Labiates have a labiate 

 corolla ; the Comfcrm are cone-bearing plants ; and so on. 



The names of the genera are derived in various ways : thus 

 either from the name of some eminent botanist, as Linnpea after 

 Linnfeus, Smithia after Smith, Hookeria after Hooker, Jussisea 

 after Jussieu, Tournefortia after Tournefort ; or from some 

 peculiarity of structure, or habit of the plants comprised in 

 them, and from various other circumstances. Thus, Crassida 

 is derived from the genus comprising plants with succulent or 

 thickened leaves; Duitaria derives its name from presenting 

 dentate roots ; Are?iaria from growing in sandy places ; Litho- 

 spenmini from its so-called seeds, or properly achsenia, having a 

 stony hardness ; and so on. 



The names of the species are also variously derived. The specific 

 names are usually written after the generic, and these taken toge- 

 ther constitute the proper appellation of a plant. The species of 

 the genus Viola, as shown by Gray, exhibit the origin of many 

 specific names. "Thus, specific names sometimes distinguish the 

 coimtry which a plant inhabits, for example, Viola canadensis, the 

 Canadian Violet; or the station where it naturally grows, as Viola 

 pali'stris, which grows in swamps, Vio^a arvcnsis, in fields ; 

 or they express some obvious character of the species, as Viola 

 rostrata, where the corolla bears a remarkably long spur, Viola 

 tricolor, which has tricoloured fiowers, Viola rotund ifoUa, with 

 rounded leaves, Viola lanceolata, with lanceolate leaves, Viola 

 pedata, with pedately -parted leaves, Viola pri/inda folia, where 

 the leaves are compared to those of a Primrose, Viola asarifolia, 

 where they are likened to those of Asarum, Viola ptibescens, 

 which is hairy throughout, &c. Frequently the species bears 

 the name of its discoverer or describer, as Viola Muhicnbergii, 

 Viola Nuttalii, &c." Specific names are written after the 

 generic, as indicated above in the different species of the genus 

 Viola; they are also commonly adjectives, and agree in gender 

 and case with the name of the genus. "When a species is named 

 after its discoverer or describer, it is usually placed in the 



