Cockayne. — Ecological Studies in E eolation . 3 



500 cm. and other parts less than 30 cm. ; the plant formations include 

 mangrove swamp, rain forest, heaths of various kinds, subglacial fell- and 

 herb-fields, varied associations of rock and debris, subantarctic southern- 

 beech forest, associations in and near hot springs, dunes, salt meadows, 

 steppes, swamps, and moors — in fact, for an equal variety an ecologist would 

 have to explore one of the larger continents in its entirety. Further, the 

 isolation of the region for a vast period of time far from any other land- 

 surface ; the absence of grazing animals, the moa (Dinornis) excepted ; 

 the diverse floral elements (Malayan, Australian, Subantarctic, &c.) ; the 

 strong endemism ; the numerous small islands where conditions are simpler 

 than on the larger ones ; and, finally, the presence of many areas whose vege- 

 tation has been changed within a very few years through the farming 

 operations of the settler, and its components replaced by exotics of quite 

 different growth-forms — all these attributes much enhance the importance 

 of New Zealand for ecological research. 



Now, although I well know that the final court of appeal in evolutionary 

 matters is experiment, still it seems to me that some few details having 

 a bearing on various phases of the evolution question selected from numerous 

 observations on a vegetation and a flora that one may venture to designate 

 '' unique " may perhaps be worth the attention of students of descent. 



II. Elementary Species. 



Few will deny, whatever be their opinions as to its truth, that the most 

 awakening contribution of late years to the evolution question has been 

 the mutation theory of De Vries. Leaving out of consideration for the 

 present the value of the theory as a means of evolution, the introduction 

 of careful experimental methods — i.e., a return to Darwin's own procedure 

 — rather than mere argument in favour of this or that dogma has given 

 new life to the study of evolution. Moreover, a change of the highest 

 moment is the substitution of elementary species* as the raw material for 

 the evolutionary process, rather than the Linnean species, which, as shown 

 below, are frequently ideas merely and not living entities. It seems well, 

 then, first of all to examine how far the doctrine of elementary species is 

 supported by the New Zealand flora, as interpreted by ecology. 



It need hardly be pointed out that the species of New Zealand taxono- 

 mists belong to the Linnean category, and that, while some refer to definite 

 and well-defined groups the individuals of which can be recognized at a 

 glance (e.g., Veronica Gilliesiana T. Kirk, Senecio cassinioides Hook, f., 

 Carmichaelia gracilis J. B. Armstg., Urtica jerox Forst. f.), others vary 

 to such an extent that there is no special set of individuals reproducing 

 a plant that matches the specific description, which is drawn up so as to 

 include a varying series of formsf which are considered to intergrade (e.g., 

 Veronica salicifolia Forst. f., Celmisia coriacea Hook, f., Asplenium bulbi- 

 ferum Forst. f., Danthonia semiannularis R. Br., and, roughly speaking, 

 perhaps 25 per cent of the vascular flora). Such " species " as these latter 

 do not really exist ; they are ideas only, and their origin has nothing to do with 

 evolution. Other " species," again, through want of a full knowledge of their 



* This is not very different, after all, from Darwin's view, who declared that " a 

 well-marked variety may therefore be considered an incipient species . . . the 

 term ' species' is one arbitrarily given to a set of individuals closely resembling each other, 

 and that it does not essentially differ from the term ' variety.' " (Darwin, 1899, p. 39.) 



t And then accepting this as a species, it is said to be " extremely variable." 



