No. 569] SHORTER ARTICLES AND DISCUSSION 



31 1 



Genera that are not orthotypk fall into the two classes al- 

 ready considered, those with a single species at the original plac 

 of publication, and those with two or more species. It is now 

 generally agreed that when only one species was mentioned this 

 should be accepted as the type. Such genera, may be called 

 luiplofijjtlc, or single-typed. When two or more species were in- 

 cluded in the original treatment of a genus, and no type was 

 designated, we have the problem of subsequent determination of 

 the type, resulting in what may be termed a logotypk genus, 

 that is, a genus with a rationally selected type species. The 

 object of selection is to determine the historical type of the 

 genus. Names must have definite applications, and historical 

 applications of generic names can be made definite by ascertain- 

 ing the historical types. The recognition of a new generic group 

 is usually based on one leading or dominant species, with the 

 others added as associate members. 



In many cases the generic type is intimated by the original 

 author in dividing the genus into subgenera or sections, in illus- 

 trating one of the species or citing illustrations published in 

 earlier works, in naming the genus with particular reference to 

 one of the species, in recording economic uses, or in giving geo- 

 graphical or other indications of greater familiarity with one of 

 the species. If the application of these or other historical cri- 

 teria leaves more than one species eligible for selection, the first 

 of the eligible species should be taken as logotype. In this way 

 it is possible to develop a consistent system of type selection that 

 will commend itselt as reasonable and lmvc the same results in 

 the hands of different students. 4 



4 Simply taking the first species under a generic name as the type would 



in the genus as the type. Kit her ,.f these methods of selecting types would 

 result in many cases of separation of generic names from their historical 

 types, but these undesirable changes in the application of names can be 



