200 ECOLOGY 



group of nearly related, although rarely, if ever, intergrading species. 

 He knows that they have different ranges and habitats, and further- 

 more that by their parthenogenetic tendencies and the rarity of the 

 staminate plant they offer to the biologist problems of exceptional 

 interest. This is but one of many cases where from an indifference to 

 the refinements of modern classification the ecologist has as yet failed 

 to perceive lines of fascinating investigation appropriate to his own 

 subject. Why should the ecologist by his own confession and pre- 

 ference be fifteen or twenty years behind the times in his taxonomic 

 equipment? 



While this is undoubtedly the rule, I am glad to say there are 

 notable exceptions. The care with which Mr. Kearney has based his 

 ecological study of the Dismal Swamp upon a large series of numbered 

 specimens, critically identified and preserved at a great centre of 

 taxonomic work, merits high praise. Other equally notable instances 

 of conscientiousness in these matters might be cited. 



In general, however, life-zones, plant formations, and plant soci- 

 eties have been indicated merely by the more conspicuous plants, 

 identified largely in the field and with but little attention to herb- 

 arium records. Were ecologists from this time on for many years 

 to explore no new territory, but merely extend their observations to 

 the less conspicuous plants and more technical genera, were they 

 to take full advantage of the most modern and detailed taxonomy, 

 were they to place correctly in its ecological class each sedge and rush, 

 each aster, lupine Antennaria, stemless violet, and Sisyrhinchium, 

 not to speak of cryptogams, they would find no lack of profitable 

 occupation or interesting results. 



In the definition of plant associations there is almost always 

 vagueness. To some extent this is inherent in the subject. Floras pass 

 into each other gradually, and sharp definition is as impossible as it 

 would be unnatural. Yet there can be no doubt that further study 

 could make the classification more definite. At present plant form- 

 ations and societies are characterized, as we have seen, usually by 

 a few typical and conspicuous plants, other plants often being men- 

 tioned as of more general distribution, occurring promiscuously in 

 differing ecological conditions. In examining ecological lists it is 

 noticeable that just these less readily classified plants are in many 

 instances those which the systematist is inclined to segregate into 

 two or more species. It is impossible to escape the conviction that 

 the ecologist by studying these segregations could often place their 

 components with greater definiteness than he does at present the 

 aggregates, thereby attaining an added completeness and precision 

 in phytogeographic groups. 



From these facts it seems clear that ecology may obtain new depth 

 by the aid of modern taxonomy. The converse is equally true. In 



