26 International Code of Nomenclature 



Rule 5. Chapter 3. Sect. 1. Naming of Taxa 



RULE 5a. Names of genera and subgenera are substantives (or adjectives 

 used as substantives) in the singular number and written with an initial 

 capital. The names may be taken from any source whatever and may even 

 be composed in an arbitrary manner. They are treated as Latin substantives. 

 RULE 5b. Generic names and subgeneric names are subject to the same rules 

 and recommendations, and from a nomenclatural standpoint they are co- 

 ordinate. 



RULE 5c. If a genus is divided into subgenera, one of the subgenera (that which 

 includes the type species of the genus) must bear the same name as the genus. 

 NOTE. Citations of authors are governed by Rule 16. 



ANNOTATIONS 



Rule 5. Genera and subgenera. Rule 5a is much like that of the 

 Botanical Code. 



Ride 5 is similar in intent to several articles in the Zoological 

 Rules, which provide that: 



1. A generic name must consist of a single word, simple or com- 

 pound, written with a capital initial letter, and employed as a 

 substantive in the nominative singular. 



2. Generic and subgeneric names are subject to the same rules and 

 recommendations, and from a nomenclatural standpoint, they 

 are co-ordinate, that is, they are of the same value. 



3. A generic name becomes a subgeneric name when the genus so 

 named becomes a subgenus, and vice versa. 



4. If a genus is divided into subgenera, the name of the typical 

 subgenus must be the same as the name of the genus. 



Rule 5 makes it clear that if a genus is found to contain two or 

 more readily differentiable groups of species, each group may be 

 recognized as a subgenus. One of the subgenera, that which includes 

 the type species, must have the same name as that of the genus. If 

 it is desired to recognize each of the groups of species as a distinct 

 genus, the subgeneric names then become generic names. 



Conversely, when two or more genera are luiited, the names of 

 the genera become the names of subgenera if subgenera are recog- 

 nized. 



The Paris (1954) revision of the Botanical Code has modified the 

 treatment of taxa between genus and species. The pertinent Article 

 (21) reads in part: 



The name of a subdivision of a genus is a combination of a generic 

 name and a subdivisional epithet connected by a term (subgenus, 

 section, series, etc.) denoting its rank. 



The epithet of a subgenus or section must not be fonned from the 

 name of the genus to which it belongs by adding the ending -aides 

 or -opsis. 

 1 he Botanical Recommendation 21 A reads: 



For a subgenus and a section the epithet is usually a substantive 

 resembling the name of a genus or repeating the name of the genus 

 itself. 



