56 BASES AND CRITERIA. 



many species because of the diverging evolution of an original stock under the 

 more or less direct control of changing habitats. A species shows a similar 

 evolution of forms, distinguishable from each other but mutually related to each 

 other by descent, as are the species of a genus. For the ecologist, the relation- 

 ship of such forms to the parent species is fully as important and even more 

 significant than their recognition. It is imperative for his purposes that this 

 relationship to the species be shown by the name as the latter shows that of 

 species to the genus. This demands the use of trinominals, which is in accord 

 with the general practice of ornithologists and mammalogists, but contrary to 

 that of many systematic botanists. The one disadvantage of the trinomial is 

 length, but this is readily obviated by using merely the initials of the specific 

 name, e. g., Achillea m. lanulosa, Ranunculus f. reptans, Galium b. scias (Clem- 

 ents, 1908:263; Clements and Clements, 1913). This has long been the 

 well-known practice of mammalogy and ornithology, e. g., Citellus t. parvus, 

 Lepus c. melanotis, Cyanocitta s. frontalis, Buteo b. calurus, etc. This or a similar 

 method is inevitable if systematic biology is to aid and not hinder the develop- 

 ment of ecology and the closely related practical sciences of agriculture, horti- 

 culture, forestry, plant pathology, economic zoology, etc. Three reasons would 

 appear to lead irresistibly to this result. The field worker must deal with units 

 which are recognizable in the field with a fair exercise of patience and keenness. 

 He must carry in mind the names and characteristics of a large number of 

 species, and he can do this only by relating them to each other. There is a very 

 definite limit to the capacity of the average memory, and this limit is greatly 

 overstepped by a system which trebles the total number of species in a region 

 and substitutes for a clearly marked genus like Astragalus 17 genera recogniz- 

 able with difficulty by the systematist and practically impossible for others. 

 Finally, while the ecologist is willing to go even farther than the systematist 

 in recognizing minor differences, providing these are based upon statistical 

 field studies and experiment and not upon herbarium specimens, the practical 

 scientist is concerned primarily with real species rather than the many varieties 

 and forms into which some of them fall. At least, when the need for a closer 

 knowledge arises in a particular case, it is infinitely easier and more helpful to 

 deal with the variations of a well-recognized species than with a dozen binom- 

 ials, none of which to him have the slightest relation to each other. 



If taxonomy is to be helpful to anyone but taxonomers, it must clearly do 

 several things. It must recognize the field as the only adequate place for 

 determining new forms, and must commit itself unreservedly to the methods 

 of statistical and experimental study. It must restrict the use of the binomial 

 to species in the Linnean and Grayian sense and employ the abbreviated 

 trinomial for all segregates of such species, except in the rare cases where a 

 coordinate species has been overlooked. It must realize that the splitting of 

 genera only places so many stumbling-blocks in the way of all non-systematists, 

 and makes them still more unsympathetic with such methods. Finally, it must 

 recognize that a manual which can be used with success only by the syste- 

 matist fails signally in its purpose, and be willing to construct keys and descrip- 

 tions primarily for foresters, agronomists, grazing ecologists, and others whose 

 knowledge of taxonomy is slight. Upon such a basis, species and genera will 

 not only have vastly greater usefulness, but greater significance also to the 

 ecologist, and he will be encouraged to do his share by handling them with 

 greater accuracy and certainty. 





