258 A TEXT-BOOK OF GRASSES 



CODES OF BOTANICAL NOMENCLATURE 



282. Botanists have recognized the necessity of being 

 governed by a definite system in nomenclatorial matters, 

 and many have adopted sets of rules or codes. The best 

 known of the earlier codes is that adopted at the Inter- 

 national Botanical Congress held in Paris in 1867. The 

 report was edited by Alphonse de Candolle and the Eng- 

 lish translation is entitled "Laws of Botanical Nomencla- 

 ture." The report should be read by all interested in 

 nomenclature. 



283. Vienna code. The most important recent code 

 is that adopted by the International Botanical Congress 

 held at Vienna in 1905, and entitled, "International 

 Rules of Botanical Nomenclature." A few of the princi- 

 ples are here excerpted in order to indicate the general 

 trend of the rules. 



Botanical nomenclature begins with the "Species Plantarum" 

 of Linnaeus (1753) for all vascular plants. (Art. 19.) 



However, to avoid disadvantageous changes in the nomen- 

 clature of genera by the strict application of the rules of nomen- 

 clature, and especially of the principle of priority in starting from 

 1753, the rules provide a list of names which must be retained in 

 all cases. The list forms an appendix to the rules [usually referred 

 to as "list of nomina conservanda"]. (Art. 20.) 



No one is authorized to reject, change or modify a name (or 

 combination of names) because it is badly chosen, or disagreeable, 

 or another is preferable or better known, or because of the existence 

 of an earlier homonym which is universally regarded as non-valid, 

 or for any other motive either contestible or of little import. 

 (Art. 50.) 



When a species is moved from one genus into another, its specific 

 epithet must be changed if it is already borne by a valid species of 

 that genus. (Art. 53.) 



The list of nomina conservanda referred to under article 20 

 includes the following American grass genera: 



