26 INTHODUCTION. 



II. Classification. 



It has been said above that descriptions of plants should, as near as pos- 

 sible, be arranged under natural divisions, so as to facditate the comparison 

 of each plant with those nearest allied to it. 



The descriptions of plants here alluded to are descriptions of species, the 

 natural dhusions of the Flora refer to natural grovps of species. 



A Species comprises all the individual plants which resemble each 

 other sufficiently to make us conclude that they are all, or may have been 

 all, descended from a common parent. These individuals may often differ 

 from each other in many striking particulars, such as colour of the flower, 

 size of the leaf, etc., but these particulars are such as experience teaches us 

 are liable to vary in the seedUngs raised from one individual. 



When a large number of individuals of a species differ from the others in 

 any striking particular, they constitute a variety. If the variety generally 

 comes true from seed it is often called a race. 



A Variety can only be propagated with certainty by grafts, cuttings, 

 bulbs, tubers, or any other method which produces a new plant by the 

 development of one or more buds taken from the old one. A race may vrith 

 care bo propagated by seed, although seedlmgs wLU always be liable, under 

 certain circumstances, to lose those particulars which distinguished it from 

 the rest of the species. A real species will always come true from seed. 



The known species of plants (now near 100,000) are far too numerous for 

 the human mind to study without classification, or even to give distinct in- 

 dividual names to. To facilitate these objects, an admirable system, invented 

 by Linnaeus, has been universally adopted, viz. one common substantive name 

 is given to a number of species which resemble each other more than they 

 do any other species ; the species so collected under one name are collec- 

 tively called a Genus, the common name being the generic name. Each 

 species is then distinguished from the others of the same genus by the 

 addition of an adjective epithet or specific name. Every species has thus a 

 botanical name of two words. In Latin, the language usually used for the 

 piu-pose, the first word is a substantive, and designates the genus ; the second, 

 an adjective, indicates the species. In English, the adjective specific name 

 comes before the substantive or generic one. 



Thegenera thus formed being still too numerous for study without further 

 arrangement, they have been classed upon the same principles, viz. genera 

 which resemble each other more than they do any otlier genus, have been 

 collected together into groups of a higher degree, called Families or Natural 

 Orders, to each of which a common name has been given. This is however 

 for the purpose of study and comparison. To speak of a species, to refer to 

 it aud identify it, all that is necessary to give is the generic and specific name. 



The name of a family in Latin is an adjective plural, usually taken from 

 the name of some one typical genus, supposed to be the best known or the 

 most marked. Such names can only be translated into English by the 

 addition of the word plants to a plural adjective, or by using the name of 

 the typical genus as an adjective added to the word family or Order. Thus 

 SanunculacecB is the Latin name of the family of which Ranunculus is the 

 typical genus. In English we would render it by the Ranunculus family 

 (or Order) or Ranunculaceous Plants. 



The number of species included in a genus, or the number of genera in a 



