78 MEDICAL MYCOLOGY 



Chapter III. — Names of Taxonomic Groups (Art. 15-72, Rec. Ill — L). 

 Section 1. — General Principles: priority (Art. 15-17, Rec. III). 



Art. 15. The purpose of giving a name to a taxonomic group is not 

 to indicate the characters or the history of the group, but to supply 

 a means of referring to it. 



Art. 16. Each group with a given circumscription, position, and 

 rank can bear only one valid name,* the earliest that is in accordance 

 with the Rules of Nomenclature. 



Art. 17. No one may change a name (or combination of names) 

 without serious motives, based either on more profound knowledge 

 of facts or on the necessity of giving up a nomenclature that is con- 

 trary to the Rules. 



Recommendation III. Changes in nomenclature should be made only after ade 

 quate taxonomic study. 



Section 2.— The Type Method (Art. 18, Rec. IV-VII). 



Art. 18. The application of names of taxonomic groups is deter- 

 mined by means of nomenciatural types. A nomenclatural type is 

 that constituent element of a group to which the name of the group 

 is permanently attached, whether as an accepted name or as a syno- 

 nym. The name of a group must be changed if the type of that name 

 is excluded (see Art. 66). 



The type of the name of an order or suborder is a family, that of 

 the name of a family, subfamily, tribe or subtribe is a genus, that of 

 a generic name is a species, that of the name of a species or group of 

 lower rank is usually a specimen or preparation. In some species, 

 however, the type is a description or figure given by a previous author. 

 Where permanent preservation of a specimen or preparation is im- 

 possible, the application of the name of a species or subdivision of a 

 species is determined by means of the original description or figure. 



Note. — The nomenclatural type is not necessarily the most typical or repre- 

 sentative element of a group; it is merely that element with which the 

 name of the group is permanently associated. 



Recommendations : 



IV. When publishing names of new groups authors should indicate carefully the 

 subdivision which is the type of the uew name: the type-genus in a family, the 

 type-species in a genus, the type-variety or specimen in a species. This type deter- 

 mines the application of the' name in the event of the group being subsequently 

 divided. When describing new species, varieties or forms of parasitic plants, 

 especially Fungi, the host plant of the type should be indicated. 



V. When revising a genus an author should state which species he accepts as 

 the nomenclatural type. 



VI. In selecting a nomenclatural type for a genus of non-vascular Cryptogams, 

 botanists should, where possible, choose a species that will fix the generic name 

 as it is now commonly applied. 



*In genera and groups of higher rank the valid name is the earliest name pub- 

 lished with the same rank, provided that this is in conformity with the Eules of 

 Nomenclature and the provisions of Arts. 20 and 21. 



In subdivisions of genera the valid name is the earliest name published with the 

 same rank, provided that this name and its combination with the generic name 

 are in conformity with the Eules of Nomenclature. 



In species and groups of lower rank the valid name is the binarj^ or ternary 

 combination containing the earliest epithet published with the same rank, provided 

 that this combination is in conformity with the Eules of Nomenclature. 



