THE AMERICAN BOTANIST. 31 



ableness in this position ; and it is taken not only by the 

 Neo-Amcrican School, but has long been acted upon by 

 most of the botanists of Continental Europe. Its practi- 

 cal disadvantage in this country is that it both entails 

 marked changes in the existent nomenclature of American 

 plants, and also, as will be noted later, is impossible of 

 exact application. It is a fact, however, that the Neo- 

 Americans give this principle an extension far beyond that 

 followed by any of the continental botanists. 



Second, it happened in early Post-Linn^an days that 

 the names first given to Genera very often became replaced 

 by others, either because the later botanists did not know 

 of the earlier names, or because they thought the earlier 

 names not well considered or properly published, or for 

 various other reasons ; and thus the later generic names 

 vety often became firmly fixed in botanical nomenclature. 

 TheGrayan School holds that in such cases the well-estab- 

 lished name is to be retained, even though of later date, 

 and in this they are in agreement with all the leading 

 botanical workers of England find Continental Europe. 

 Since many puzzling questions have arisen as to just 

 where the line should be drawn between those names 

 which should be displaced- for earlier ones and those which 

 should not-, the Berlin botanists adopted a rule, known as 

 the Berlin rule, now followed by most botanists except the 

 Neo-Americans, that any generic name which failed to 

 achieve acceptance for fifty years after its publication 

 should not now be revived to displace a name which has 

 become well fixed. The practical effect of this rule is to 

 retain the great body of existent nomenclature. The Neo- 

 American School, on the contrary, holds that the very 

 earliest name given to a genus should be restored, regard- 

 less of whether or not they have been used in the mean- 

 time. The application of this rule necessitates an immense 

 number of changes, and to it more than to any other 

 cause is the present confusion in nomenclature due. The 

 Neo-Americans, however, have not Ijcen able to win the 

 support of any of the English or Continental botanists, 

 and they stand quite alone in their application of it. 



