1919] REIIDER, NEW SPECIES, VARIETIES AND COMBINATIONS 45 



residues may perhaps be put into practice. The method of taking the first 

 species in a genus or the first citation or synonym in a species is an artificial 

 makesliift and not to be recommended. In genera to make the selection 

 of the type dependent, as recommended in the examples under art. 45, on 

 subsequent publications where the original extent and circumscription of 

 the genus often is considerably altered, is certainly against the principle of 

 priority, and as it thus violates one of the fundamental princi2)les of the 

 Code, we may consider ourselves justified in disregarding this recommenda- 

 tion. There will be, of course, cases when the ty]:>e method will result in 

 displacing generally accepted names, or cause considerable inconvenience, 

 but this is unavoidable, if one follows consistently any set of rules. In the 

 case of a generic name it may be saved by including it under the nomina 

 conservanda, and in a case like Ulmus campestris the name may be re- 

 jected by taking recourse to art. 51, 4 of the rules. 



Another source of different oi)ini()ns is article 50, arising chiefly from the 

 fact that no distinction is made between valid names and valid taxonomic 

 groups, that is between nomenclatorial and taxonomic validity. The word- 

 ing of the rule; " No one is authorized to reject, change or modify a name 

 . . , because of the existence of an earlier homonym which is universally 

 regarded as non-valid," is unfortunate. The ])hrase " universally regarded 

 as non -valid " seems contradictory in itself, for a name is either valid or 

 non-valid, depending on whether it is formed according to the rules or not, 

 and it cannot be made so by general consent. This becomes clear by the 

 revised article 56 which reads in part: " By valid name is implied a name 

 and especially a combination of names formed in accordance with the rules 

 of nomenclature." The strict adherence to this ruling will exclude a con- 

 siderable number of homonyms which otherwise tend to make nomenclature 

 unstable. As names that have become synonyms by change of generic or 

 specific limitations may be revived at any time by another change in the 

 taxonomic valuation of genera or species, I have termed non-valid 

 unconditional synonyms, and synonyms for taxonomic reasons conditional 

 synonyms (see Rhodora xvii, 61, footnote). As an exam])le, Picea carta- 

 densis (Mill.) Britton, Sterns & Poggenburg, may be cited. This name 

 cannot stand on account of the older P. canadensis (L) Link which is the 

 correct name of the Hemlock Spruce under the genus Picea. Even if Tsuga 

 is now recognized as a distinct genus by almost all botanists and therefore 

 Picea canadensis Link referred to Tsuga canadensis as a synonym, this 

 should not make any difference, since at any time botanists may unite 

 Picea and Tsuga again and thereby cause P. canadensis Link to be revived. 

 A similar case is Malus florihunda Sicb., which if transferred to Pyrus should 

 be changed to P, pidcherrima Ascherson & Graebner and not be called P. 

 florihunda Voss, on account of the older homonym P. florihunda Lindley, 

 even though according to the author's view that species belongs to Sorbus 

 or Aronia, but as there arc botanists who unite Pyrus, Malus, Sorbus and 

 Aronia, and others who unite Malus and Pyrus and keep Sorbus dislinct. 

 Pyrus florihunda Voss would under certain generic hmitations keep its 



