32 THE AMERICAN BOTANIST. 



The difference between the two schools then lies pri- 

 marily in this, that while both accept priority as the basal 

 principle, the one school maintains that, so far as the past 

 is concerned, this is to be applied with judgment, and in 

 such a way as to cause a minimum of inconvenience by re- 

 taining the great body of existent nomenclature ; the 

 other school holds that priority should be applied rigidly 

 and absolutely to all names, judgment being allowed no 

 place in the s^^stem. In defence of their position the Neo- 

 Americans hold that finality- in nomenclature is not pos- 

 sible under the Grayan system, because, where judgment 

 is given a place, there will be differences of opinion and 

 hence instability, while they claim that underthe absolute 

 priority system final stability is possible. They admit 

 that the application of absolute priority will cause much 

 inconvenience through the abandonment of so much of the 

 existent nomenclature, but they hold that the final advan- 

 tage of stability v^'ill more than compensate for the tem- 

 porary inconvenience. Now as to these positions two 

 things are to be said. First, the Grayan School has met 

 the diflficulties as to instability due to individual differ- 

 encce of opinion by the adoption of the Kew and Berlin 

 rules, which give as absolute and definite a basis for their 

 system as absolute priority gives to that of theNeo-Amer- 

 icans, while their S3^stem retains most of the existent no- 

 menclature where the Neo- American system abandons it. 

 Second, priority applied absolutely, and excluding the in- 

 stability due to differences of opinion or judgment, is 

 proving impossible of application. In many cases it is im- 

 possible to tell which of two names for a given plant is the 

 oldest, since early publications are often not dated or bear 

 dates known to be wrong ; in other cases it is impossible 

 to tell to which of several species or genera a given early 

 very generalized description applies ; and in other cases it 

 is impossible to saj'^ whether certain names are not inad- 

 missable through the brevity, indefiniteness, errors or ob- 

 scurity of their publication. In all these and many other 

 cases, judgment does come into play, and with it differ- 



