Volcanic Plateau, or the 140 species of the Tararua Mountains. 

 But these last figures are not so strikingly different when the 

 isolation of Mt. Egmont and the difficulties in its original plant- 

 colonization be considered. There may be an additional reason 

 for the poverty of the North Island high-mountain flora. This 

 may be that a large percentage of the South Island high-moun- 

 tain sptecies is quite young a conclusion warranted by their 

 affinities and also by their extreme polymorphy. 



The vegetation of the high mountains differs greatly 

 according to their rainfall a point stressed later. The forests 

 are largely made up of species of Nothofagus, but there are also 

 associations where Libocedrus Bidwillii and Podocarpus Hallii 

 dominate. In herb-field and fell-field the genus Celmisia is 

 represented by many species and growth-forms (see Fig. 4). 

 There are considerable areas of tussock-grassland, which on 

 the schist mountains may ascend to the highest summits, where- 

 as the readily-weathered greywacke mountains present great 

 diversity in their rock, debris and fell-field associations. Under 

 certain circumstances subalpine-scrub made up of shrubby 

 Compositae, Epacridaceae, Rubiaceae, and species of Veronica 

 is a remarkable feature, and it may become actual forest. At 

 high altitudes the cushion-form is often greatly in evidence; 

 it is also encouraged by dry stations.. The property of dead 

 leaves and other vegetative parts remaining attached to the 

 living plant in a wet, semi-peaty condition is a fairly frequent 

 characteristic of the high-mountain plants. So, too, strong 

 xerophily is common. 



(b) The Botanical Subdivisions of the New Zealand Region. 



The Botanical Districts as proposed by me in 1917 are 

 shown on the map (Fig. 5). These districts, it must be clearly 

 understood, are provisional only, and, to quote from my article 

 where they first appeared, "will be subject to considerable 

 modification for years to come." x 



There is no need here to define the boundaries of these 

 districts, nor to cite their names since both are shown on the 

 map. Nor am I giving the characters of each district, including 

 the lists of locally-endemic species. These matters are briefly 

 dealt with in the second edition of "New Zealand Plants and 

 Their Story," p. 180 p. 194, and to this the reader is referred. 

 Here only certain critical remarks are made regarding the 

 boundaries of certain of the districts. First of all, however, the 

 principles upon which the delimiting of the districts was based, 

 may be quoted from the original article (loc. cit.). "In the 

 delimiting of a 'district' an attempt has been made to mark 

 off natural areas which are distinguished principally by the 

 following circumstances some flor:..stic (these the most im- 

 portant, since the districts are essentially floristic), some 

 ecological: (1) The presence of a more or less extensive locally 



tions of 



- Cockayne, L., " Notes on New Zealand Floristic Botany, including Descrip- 

 of New Species, etc." (No. 2). Trans. N.Z. Inst., vol. xlix, 1917, p. 62. 



