TAXONOMY OF THE HIGHER PLANTS 201 



which the reproductive process or the level of polyploidy is under investiga- 

 tion. The most effective experimental approaches in taxonomy have combined 

 work in the herbarium and field with studies in the greenhouse and experi- 

 mental plot. 



Another area of experimentation that impinges directly on our subject is 

 that concerned with gene ecology. It is not only essential that genetical vs. 

 environmental influences on the phenotype be well understood, but the 

 reactions of the genetically controlled characteristics to varying ecological 

 situations are also pertinent to an understanding of the taxonomy of a given 

 group. Real progress in this area of investigative work was touched off by the 

 contributions of Turesson (1922), which have been followed up by numerous 

 investigations. The most notable and sustained experiments are those of 

 Clausen, Keck, and Hiesey {I.e.), beginning with the setup developed by 

 Hall (1932) and extending over a period of more than thirty years. Aside 

 from the information concerning phenotypic responses of different genotypes 

 under different climatic and edaphic conditions, this work has highlighted 

 the tremendous genetical, physiological, and taxonomical complexity present 

 in plant species. A new dimension of appreciation of this complexity is cer- 

 tainly one of the major lessons for botanists provided by this area of research. 



One of the many segments of taxonomy where a job remains to be done 

 by experiment is that having to do with the variability of different types of 

 plant characters. The assessment of characters that are of taxonomic im- 

 portance, using the actual variation present in a given taxon under a con- 

 trolled set of conditions as a base for determining the potential variation 

 under the same and different patterns of conditions, must be done by experi- 

 ment. We need to know definitely which characters of plants deviate the 

 most under changed conditions and in what way. 



It may be that information of this kind will always have to be somewhat 

 limited in its application and will have to be determined anew in every plant 

 group. On the other hand, it is hoped that a quantity of data will eventually 

 provide the basis for certain generalizations helpful to the taxonomist. The 

 point may be recognized that the ultimate strength of a classification is de- 

 pendent upon the accuracy of evaluation of the characters used in developing 

 that classification. Furthermore, it is important that the widest possible as- 

 sortment of characters be evaluated and used. 



THE PROBLEM OF COMMUNICATION 



Plant names are basic to accurate communication in botany. Like the 

 terms of description and designation in science generally, each of them car- 

 ries a precise meaning if properly used. Also, like terms, their precise meaning 

 may be devalued by improper use and altered completely by misapplication 

 to the wrong plant. It has been difficult to develop a foolproof system by which 



