December 28, 1917] 



SCIENCE 



625 



systematist reacts on the conclusions of 

 those who cite the names of plants. 



So fundamental is this contribution of 

 the systematist that we should now be very 

 cautious in talking of heredity in plants at 

 all until we have redefined their forms. 

 The records of variation, as such, do not 

 constitute definitions, but only departures 

 from assumed norms. 



The definitions of the systematist, who 

 critically survej-s a wide range of material 

 for comparison rather than for divergence, 

 apply not only to the assemblages we know 

 as species, but also to the minor forms that 

 seem to have descriptive unity. If I were 

 now working with anj'- group of plants in 

 an experimental way touching develop- 

 ment and evolution, I should want first to 

 turn the whole group over to a conservative 

 sj^stematist for careful review. 



I had hoped that, in the beginning of 

 the plant-breeding studies, the breeder 

 would also be a pronounced systematist 

 that he would aid us in the definition of 

 the forms of plants, and bring his experi- 

 mental studies to bear in tracing the prob- 

 able course of evolution up to this epoch, 

 that is, that he would contribute more freely 

 to the knowledge of origins. I still think 

 that we shall find the experimenter relating 

 his work more closely to systematic botany 

 as soon as the systematist takes cognizance 

 of the plant-breeder, and the plant-breeder 

 is satisfied that he must analyze his meas- 

 urements in terms of biological definition 

 and classification. I doubt the adequacy of 

 some of the biometrical computation, and I 

 regret the frequent neglect of herlDarium 

 studies whereby vegetation-factors rather 

 than measurement-factors may be strongly 

 emphasized. 



It is not unlikely that the ecologist falls 

 into false comparisons by carelessness in 

 identification, or by inattention to critical 

 differentiations. It really matters very 



much whether a given distribution repre- 

 sents one specific type, or two or more very 

 closely related types; in fact, the signifi- 

 cance of an ecological study may depend 

 directly on allied taxonomic relationships. 



Certain phases of the intermediate field 

 between taxonomy and genetics I discussed 

 two years and more ago in this city before 

 the American Philosophical Society, and 

 suggested a definite program of combined 

 systematic and experimental work; there- 

 fore I shall not enlarge on this subject here, 

 although it merits further attention. It 

 may be noted in passing, however, that the 

 more enthusiastic definition of forms de- 

 mands a refined and more exact art of 

 phytography, and it should lead also in the 

 direction of classification. The marked 

 variations may well find place in a taxo- 

 nomic treatment rather than to be studied 

 merely as separates. The remarkable mu- 

 tations of Nephrolepis, for example, af- 

 ford excellent material for systematic de- 

 scriptive study. 



Much of the earth is yet to be explored 

 for the forms of life. There are fertile re- 

 gions yet untouched. One collection in 

 Papua yielded some 1,100 new orchids. 

 Remarkable collections of novelties con- 

 tinue to come to our herbaria, many of 

 them from regions not very remote. Not 

 nearly all the plants of the globe are 

 known. The systematist must continiially 

 be better trained, for he has the task of 

 understanding the older accumulations as 

 well as adjudging the new. He makes in- 

 creasing contributions to plant geography 

 and distribution, and gives us an enlarged 

 judgment on the character of the countries 

 of the earth as indicated by their vegeta- 

 tion. In fact, we never understand a coun- 

 try before we know its plant life. The con- 

 tributions made recently by Forrest, "Wil- 

 son, Purdom and others to the geography 



