39 



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 macrothrix or Andropogon 

 ternatus subsp. A. macrothrix)-^ Herniaria hirsuta var. diandra (not Herniaria diandra or Herniaria 

 hirsuta var. H. diandra)-^ forma nanus, forma maculatum. 



Secoxumendatiou. 



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. angusttf alius , Ranunculus acris subsp. Friesianus). 



XVbi»- Special forms are named preferably after the host species; if desired double 

 names may be used. Examples: Puccinia Hieracii f. sp. villosi, Pucciniastrum Epilobii f. sp. Abieti- 

 Chamaenerii. 



Art. 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. 



Examples. — The following are admissible: Rosa Jundzillii var. leioclada and Rosa glutinosa 

 var. Uioclada; Viola tricolor var. hirta, in spite of the existence already of a different species named 

 Viola hirta. The following are incorrect: Erysimum hieraciifolium subsp. strictum var. longisiliquum 

 and E. hieraciifolium subsp. pannonicum var. longisiliquum — a form of nomenclature which allows 

 two varieties bearing the same name in the same species. 



Recommendation . 



XVI. Botanists are recommended to use as little as possible the privilege granted in the 

 second part of article 29, in order to avoid confusion and mistakes and also to reduce to a minimum 

 the necessary changes of name when the subdivisions of species are raised to specific rank or 

 vice versa. 



Art. 30. Forms and half-breeds among cuHivated plants should receive fancy 

 names, in common language, as different as possible from the latin names of the 

 species or varieties. When they can be traced back to a species, a subspecies or a 

 botanical variety this is indicated by a succession of names. 



Example: Pelargonium zonale M^s- Pollock. 



§ 5. Names of hybrids and half-breeds (mules). 



Art. 31. Hybrids between species of the same genus, or presumably so, are 

 designated by a formula and, whenever it seems useful or necessary, by a name. 



The formula consists of the names or specific epithets of the two parents in 

 alphabetical order and connected by the sign x. When the hybrid is of known 

 experimental origin the formula may be made more precise by the addition of the 

 signs $, c^. 



The name, which is subject to the same rules as names of species, is distin- 

 guished from the latter by absence of an ordinal number and by the sign x before 

 the name. 



