RULES OF NOMENCLATURE 53 



Section 6. Conditions and Dales of Valid Publication of 

 Names {Art. 37-45, Rcc. XXI-XXIX) 



Art. 37. A name of a taxonomic group is not validly published unless it is both (1) 

 effectively published (see Art. 36), and (2) accompanied by a description of the group 

 or by a reference to a previously and effectively published description of it. 



Art. 38. From January- 1, 1935, names of new groups of recent plants, the Bacteria 

 excepted, are considered as validly published only when they are accompanied by a 

 Latin diagnosis. 



Art. 40. A name of a taxonomic group is not validh' published when it is merely 

 cited as a synonjTn. 



Art. 42. A name of a genus is not validly published unless it is accompanied (1) 

 by a description of the genus, or (2) by the citation of a previously and effectively 

 published description of the genus under another name, or (3) by a reference to a 

 previously and effectively published description of the genus as a subgenus, section 

 or other subdivision of a genus. 



Art. 43. The name of a monotypic new genus based on a new species is validated 

 (1) by the provision of a combined generic and specific description, (2) by the pro- 

 vision of a plate with analyses showing essential characters; but this applies only to 

 plates and generic names published before January 1, 1908. 



Art. 44. The name of a species or of a subdivision of a species is not validly pub- 

 lished unless it is accompanied (1) by a description of the group, or (2) by the citation 

 of a previously and eflfectiveh' published description of the group under another name, 

 or (3) by a plate or figure with analyses showing essential characters; but this applies 

 only to plates or figures published before January 1, 1908. 



Art. 45. The date of a name or of an epithet is that of its valid publication (see 

 Art. 19, 36). For purposes of priority, however, only legitimate names and epithets 

 published in legitimate combinations are taken into consideration (see Art. 60). In 

 the absence of proof to the contrary, the date given in the work containing the name 

 or epithet must be regarded as correct. 



Botanists will do well in publishing to conform to the following recommendations: 



XXI. Xot to publish a new name without clearly indicating whether it is the 

 name of a family or a tribe, a genus or a section, a species or a variety; briefly, with- 

 out expressing an opinion as to the rank of the group to which the name is given. 



Xot to publish the name of a new group without indicating its type (see Recom- 

 mendation IV). 



XXII. To avoid publishing or mentioning in their publications unpublished 

 names which they do not accept, especially if the persons responsible for these names 

 have not formally authorized their publication (see Recommendation XV (e). 



XXVI. To give the etymology of new generic names and also of new epithets 

 when the meaning of these is not obvious. 



XXVII. To indicate precisely the date of publication of their works and that of 

 the placing on sale or the distribution of named and numbered plants when these are 

 accompanied by printed diagnoses. In the case of a work appearing in parts, the 

 last published sheet of the volume should indicate the precise dates at which the 

 different fascicles or parts of the volumes were published as well as the number of 

 pages in each. 



XXVIII. When works are published in periodicals, to require the publisher to 

 indicate on the separate copies the date (year and month) of publication and also the 

 title of the periodical from which the work is extracted. 



