84 International Code of Nomenclature 



Rule 19, Recommendation 19a. Changes in Names of Taxa 



RULE 19. When two or more taxa of the same rank are united, the oldest 

 legitimate name or (in species and subspecies) the oldest legitimate epithet 

 is retained. If the names or epithets are of the same date, the author who 

 first unites the taxa has the right to choose one of them, and his choice 

 must be followed. 



RECOMMENDATION 19a. Authors who have to choose between two generic 

 names should note the following recommendations: (1) Of two names of 

 the same date, to prefer the one which was first accompanied by the de- 

 scription of a species. (2) Of two names of the same date, both accompanied 

 by descriptions of species, to prefer the one which, when the author makes 

 his choice, includes the larger number of species. (3) In cases of equality 

 from these various points of view, to prefer the more appropriate name. 



ANNOTATIONS 



Rule 19. The genera Micrococcus Cohn 1872 and Staphylococcus 

 Rosenbach 1884 were united by Hucker who correctly chose the 

 generic name Micrococcus as having priority. 



The corresponding Article of the Botanical Code is essentially 

 the same. 



The Zoological Rules provide that when two or more genera or 

 subgenera are united, the genus formed must take the oldest available 

 generic or subgeneric name of its components. The rule just quoted 

 applies as well when two or more species or subspecies are united to 

 form a single species or subspecies. 



Recomviendation 19a. This Recommendation corresponds to that in 

 botany. 



