128 GENERAL SYSTEMATIC BACTERIOLOGY 



e. Adopt unpublished names found in travellers' notes and herbaria, attribut- 

 ing them to the authors concerned, only when those concerned have approved the 

 publication. 



f . Avoid names which have been used before in the genus, or in any closely 

 allied genus, and which have lapsed into synonymy (homonyms). 



Comment. The Zoological Code reads: "A specific name is to be 

 rejected as a homonym when it has previously been used for some other 

 species of the same genus." This recommendation should as far as 

 practicable be given the force of a rule. 



g. Do not name a species after a person who has neither discovered, nor 

 described, nor figured, nor in any way studied it. 



h. Avoid specific names formed of two words. 



Comment. Bacillus acidi lactici is probably valid inasmuch as the 

 specific name refers to a single concept, but it is not a form to pattern 

 after. This, of course, does not validate such a name as Bacillus coli 

 communis, which is a trinomial. 



Article 27. Two species of the same genus cannot bear the same specific name, 

 but the same specific name may be given in several genera. 



Example : Arabis spathulata DC. and Lepidium spathulatum Phil, are valid as 

 two names of Crucifers; but Arabis spathulata Nutt. in Torr. and Gray cannot be 

 maintained, on account of the existence of Arabis spathulata DC, a name previ- 

 ously given to another valid species of Arabis. 



Article 28. Names of subspecies and varieties are formed like specific names 

 and follow them in order, beginning with those of the highest rank. The same 

 holds for subvarieties, forms, and slight or transient modifications of wild plants 

 which receive a name or numbers or letters to facilitate their arrangement. Use 

 of a binary nomenclature for subdivisions of species is not admissible. 



Examples: Andropogon ternatus subsp. macrothrix (not Andropogon macro- 

 thrix or Andropogon ternatus subsp. A. macrothrix) ; Herniaria hirsuta var. diandra 

 (not Herniaria diandra or Herniaria hirsuta var. H. diandra) ; forma nanus, forma 

 maculatum. 



Recommendation. XV. Recommendations made for specific names apply 

 equally to names of subdivisions of species. These agree with the generic name 

 when they have an adjectival form {Thymus Serpyllum var. angustifolius, Ranun- 

 culus acris subsp. Friesianus). 



Special forms are named by preference by means of the names of the host 

 species. In making such names one may employ double names. Examples: 

 Puccinia Hieracii f. sp. villosi, Pucciniastrum Epilobii f. sp. Abieti-Chamaenerii. 



Article 29. Two subspecies of the same species cannot have the same name. 

 A given name can only be used once for a variety of a given species, even when 

 dealing with varieties which are classed under different subspecies. The same 

 holds for subvarieties and forms. 



On the other hand the same name may be employed for subdivisions of different 

 species, and the subdivisions of any one species may bear the same name as other 

 species. 



