44 International Code of Nomenclature 



Rule 7. Chapter 3. Sect. 1. Naming of Taxa 



RULE 7. Names of subspecies (varieties) are ternary combinations consisting 

 of the name of the genus followed by specific and subspecific epithets in 

 order. 



Epithets of subspecies (varieties) are formed like those of species; when 

 adjectival in form and not used as substantives they agree in gender with 

 the generic name. 



Neither within the same species nor within the same genus may two 

 subspecies bear the same subspecific epithet. 



If the species is divided into subspecies, the subspecific epithet of the 

 subspecies containing the type of the species must be the same as that of 

 the species. 



NOTE. Names of species and of subspecies (varieties) from a nomenclaturol 

 point of view are coordinate (of equal value) and are subject to the same 

 rules and recommendations. 



NOTE. The words subspecies and variety are alternative designations for 

 the same taxonomic rank; they are synonyms. The use of the term sub- 

 species is preferable. 



ANNOTATIONS 

 Rule 7. The name of a subspecies (or variety) is a trinomial made 

 up of a generic name followed by a specific epithet and this, in turn, 

 by a subspecific epithet. As provided in Rule 14, an author when 

 proposing the name of a subspecies should make clear its subspecific 

 status. The epithets preferably are separated by the abbreviation 

 indicating a subspecies (variety) , or this may be omitted. One may 

 write Bacillus subtilis subsp. 7nger or Bacilhis subtiUs var. niger or 

 Bacillus subtilis niger. The last listed method is most often used in 

 biology, but has the disadvantage of not being directly distinguish- 

 able from an illegitimate trinomial name of a species. In other words, 

 the name Bacillus fluorescens liquefaciens proposed as the name of a 

 species was illegitimate because it had two specific epithets; it was 

 not proposed as the name of a subspecies. 



The sixth edition of Bergey's Manual of Determinative Bac- 

 teriology recognized two varieties or subspecies of Bacillus subtilis: 

 Bacillus subtilis aterrimus and B. subtilis Jiiger. A third should have 

 been recognized, B. subtilis subtilis, to inckide the type of the species. 



Note that species may be divided into subdivisions of lower rank 

 than subspecies and that subspecies may also be subdivided. These 

 subdivisions are considered under Rule 8. Not all of the rules and 

 recommendations applicable to species and subspecies are applicable 

 to taxonomic ranks lower than subspecies. 



Recommendations 6a, 6b and 6c apply to subspecific epithets as 

 well as to specific epithets. 



The name of a subspecies is a ternary combination; the use of a 

 binary combination as the name of a subspecies is therefore not ad- 

 missible. Example: Mycobacterium tuberculosis var. avium or Myco- 

 bacterium tuberculosis avium, not Mycobacterium tuberculosis var. 

 M. avium,. 



