INTRODUCTION. 17 



them to be more and more ignored. There are several cogent reasons why nomenclature 

 should concern itself less with a fugitive stability derived from rules and give much more 

 attention to one based upon excellence and usability. In the first place, it seems clear 

 that the rights of thousands of users outweigh those of the scores of systematists, and 

 that usability and attractiveness must rank with stability as primary qualities of a nomen- 

 clature. This is strikingly true when the future is weighed against the present, and it is 

 realized that the codes of to-day would fix existing conditions for all time. While there 

 seems little danger of this to one who believes that the methods and results of each 

 generation of scientists will show an advance upon those of the preceding, it is unfortunate 

 that many systematists appear to feel that nomenclature is a thing apart from science, 

 and that progress in it can be prevented by codes. 



Essentials of stability. — Those who hoped that application of the rule of priority 

 would lead to a stable and universal nomenclature in a few years have been greatly disap- 

 pointed and have come to realize that strict priority affords a less practicable basis than 

 usage. The outcome for the flowering plants is still in doubt, but it is suggested by 

 practically all the proposals for securing stability among the crjrptogams, which agree 

 in selecting starting-points that will disturb usage little or not at all. In the very nature 

 of the case, greater stabiUty is obtained by taking advantage of usage than by going 

 counter to it. While to many, priority has seemed to have some special virtue as a 

 basis for nomenclature, its merit must be measured by its practicability, and by this 

 test it is little if any better than usage. This is best shown by the fact that even the 

 most thoroughgoing priority, that dating from the "Species Plantarum," is based 

 upon usage in that it ignores all previous work. 



To some systematists stability has seemed to be achieved when the adherents of a 

 particular code were in essential agreement as to its concrete application, a condition 

 not always met. As an actual fact, however, stability exists only when a particular 

 code of rules has universal sanction and gives the same results in application. Such a 

 condition seems distant at present, and for many reasons it is to be hoped that it wiU 

 not come about until systematists have a wider vision and truer perspective in matters 

 of nomenclature. A further reason why stability is a will-o-the-wisp lies in the effect 

 of segregation, for it must be recognized that stability consists as much in having the 

 same unit for a name as in having the same name for a unit. It lies also in respecting 

 existing landmarks and in relating all new knowledge to these. This in itself involves 

 a thorough change in the current practice, at least in America, and demands that the 

 trinomial be brought into regular use for segregates of valid species. The binomial 

 should be restricted to the species as including all of its subspecies, and the trinomial 

 would always serve to distinguish the subspecies and to relate it to its proper specific 

 stock (cf. Clausen, 1922). Finally, it seems impossible to think that blundering, mean- 

 ingless, or excessively long names can be stabilized. They detract from the value and 

 usability of taxonomy, as well as its attractiveness, and true stability can be obtained 

 only by correcting or ignoring them. 



Practical nomenclature. — If the names of plants are to meet the needs of all those that 

 use taxonomy or would use it, they should be brief, significant, well-constructed, and 

 euphonic. In the present series of monographs an endeavor is made to secure maximum 

 currency for the names used by taking into account the needs of the amateur and the 

 general scientist as well as those of the speciaUst. This is achieved in the first place 

 by retaining the traditional species, under which the segregates are assembled, while 

 the names of the latter are retained in so far as their quaUty permits. Even while much 

 latitude in regard to varietal and subspecific names is allowed by both codes, continuity 

 is the essence of stability, and this can be secured only by retaining names whenever 

 possible. Because of its greater emphasis upon usage, the International Code has 



