2 Transactions. 



of botany, especially physiology and floristic botany, though its methods 

 are different from those of the latter. 



The conditions which the earth offers, in its manifold soils and climates, 

 for plant-life are extremely diverse and complex, but nevertheless there 

 exists in no few instances an apparent harmony between the conditions 

 and the plants, which is manifested in the latter by some special form either 

 of the organism as a whole or of one or more of its organs. It is obvious 

 that in attempting to correlate plant-forms with their environmental factors 

 matters are being dealt with which deeply affect the study of descent, and 

 data are accumulated which cannot be neglected by students of general 

 evolution. 



But besides being occupied by plant-adaptations* the ecologist has also 

 to do with the species of the taxonomist, since for one part of his work, 

 at any rate, the groups of individuals indicated by the specific names are 

 at present the units with which he has to deal. Furthermore, his practical 

 acquaintance with such species, and particularly with their varieties, 

 must in course of time become wide, while a variation with him is not 

 merely a taxonomic mark to be noted for purposes of classification, but 

 a physiological expression to be explained. 



Besides being concerned with the origin of adaptations and species, 

 plant-ecology deals with the arrangement of the latter into the various 

 more or less well-defined combinations entitled " plant -associations," and 

 here come in such fundamental evolutionary concepts as distribution, 

 isolation, and the struggle for existence. 



Plant-ecology itself, although studied in a more or less desultory and 

 incoherent fashion since the time of Linnaeus, may be said to date, as a 

 special branch of botany, from the publication of Warming's Plantesam- 

 fund in 1895. f At first looked at askance by the older botanists, it has 

 steadily advanced in importance. It is prosecuted by careful and enthu- 

 siastic workers in many lands, and is now almost universally recognized 

 as a field of the highest biological moment. Unfortunately, its methods 

 are for the most part extremely crude, there is but little uniformity of 

 procedure amongst its adherents, and its nomenclature is altogether un- 

 fixed. Lastly, many of the problems that await solution are amongst the 

 most difficult that science has to offer. 



Bearing the above statements in mind, it is obvious that the simpler 

 the conditions and the fewer the species involved, the easier is it to draw 

 conclusions of moment, and to state the ecological " facts," if one may so 

 designate what arise from observations made under conditions far from 

 stringent. Also, a virgin vegetation alone can give definite information on 

 many topics. Tue New Zealand biological region supplies in some mea- 

 sure the above desiderata. Its vascular flora, consisting of some 1,650 

 species, is not too great for an ecological worker to grasp ; its vegetation 

 is still in many places absolutely virgin ; its climate varies from subtropical 

 to subantarctic ;| some parts experience an annual rainfall of more than 



* The convenient term " adaptation " is used throughout this piper in a non- 

 teleological sense. 



f This statement applies rather to the ecology of plant-distribution than to that 

 general and more fundamental study of life-reactions known as " biology " by German 

 investigators. In this latter sense Darwin himself stands pre-eminent as an ecologist. 



% The subantarctic and the subarctic climates are by no means identical. Intense 

 cold plays no part in the first-named, its main characteristics being lack of sunshine, 

 frequent cold gales, constant showers, and a low average temperature all the year, with 

 but little frost in winter. 



