164 SYSTEMATIC BOTAXY. 



of a vast number of phenomena otherwise inexplicable, and offers plau- 

 sible and valid reasons for the existence of facts and processes that were 

 previously considered either unintelligible or purposeless modifications of 

 an assumed structural type. The portion of Mr. Darwin's hypothesis 

 which has perhaps received the least amount of assent has been that 

 relating to natural selection. The idea was based on that artificial pro- 

 cess of selection by means of which man has been enabled progressively 

 to improve and perpetuate the different forms of domestic animals and 

 cultivated plants. In the latter case the horticulturist is ever on the 

 look-out for variations. If he sees one that suits his purpose, such, for 

 instance, as a plant producing larger flowers than ordinary, he does all 

 that he can to perpetuate that variety by carefully selecting seed from it, 

 at the same time that he destroys or neglects other less desirable varia- 

 tions. In this manner, after a time, the selected variety becomes " fixed," 

 and a " race " is formed. On the Darwinian hypothesis a selective process 

 is supposed to occur naturally, similar to that employed by the gardener 

 or agriculturist as just explained, such selection or elimination resulting, 

 as before said, in the survival of the fittest. 



Sect. 2. NOMENCLATURE. 



Names of Plants. The Terminology of Botany establishes rules 

 for naming the parts or organs of plants, and the different charac- 

 teristics which those organs present. Nomenclature deals with the 

 naming of plants themselves as members or parts of the Vegetable 

 Kingdom ; and it furnishes the rules for naming the kinds of plants, 

 and the various groups or assemblages in which they are associated 

 in our systematic classifications of kinds. 



The primary rule in botanical (and zoological) nomenclature as 

 laid down by Linnaeus is, that every species shall have a particular 

 name, compounded of a substantive and an adjective (or substantive 

 used adjectively), luhereof the former indicates the genus, and the 

 latter the species. 



This rule of naming may be compared with the common usage of sur- 

 names and Christian names the former indicating the family to which a 

 man belongs, while the latter admits of his being spoken or written ^about 

 without the necessity of adverting, except for special purposes, to his per- 

 sonal peculiarities or his relationship to the other members of his family. 



These scientific names of plants were originally established in 

 Latin, because Latin was the general language of science at the 

 time they were introduced; and they will be retained with advantage 

 so long as diversity of language exists, since they ensure to all plants 

 and animals names which have universal acceptation, and which, 

 like the Arabic numerals 1, 2, 3, &c., are equally comprehensible to 

 the educated of all nations, and, moreover, they are more definite 

 and precise in their signification than ordinary vernacular appel- 

 lations. 



