Kirx.—On the Naturalized Plants of Port Nicholson. 363 
speedily destroy the undergrowth, admitting the light and air. These in their 
turn act unfavourably on the larger vegetation which has attained its 
growth in a dark damp atmosphere, and the injurious agency gradually 
extends over a constantly widening area. But in this colony it rarely 
happens that the process of displacement passes into complete replacement ; 
it rarely or never results in the extirpation of indigenous species, although 
it greatly reduces the number of individuals. The admission of air and 
light, while unfavourable to certain plants, tends to increase the vigour of 
others, which exhibit a luxuriant growth they had never before displayed, 
and at length a turning-point is reached, the invaders lose a portion of 
their vigour and become less encroaching, while the indigenous plants find 
the struggle less severe and gradually recover a portion of their lost 
ground, the result being the gradual amalgamation of those kinds best 
adapted to hold their own in the struggle for existence with the introduced 
forms, and the restriction of those less favourably adapted to habitats which 
afford them special advantages. This, in brief, is a statement of the 
phenomena now in progress throughout the colony; but at present we are 
not in a position fully to appreciate several of its bearings. 
It can scarcely be expected that those who were familiar with the general 
features of the vegetation of New Zealand before they were modified or 
changed by the progress of settlement will at once accept the statement I 
have given as correct. They have witnessed the steady onset of axe and 
fire, the unceasing advance of cattle and sheep, and they have been so 
impressed with the almost total extinction of many striking plants over 
areas where they were formerly abundant, as to have lost sight of the 
tenacity with which plants in general maintain their existence even under 
unfavourable conditions, of the surprising power of adaptation which 
they often exhibit under changed circumstances, and are led to the 
conclusion that sooner or later the majority of our native plants 
must inevitably become extinct. I can only share in this fear to a 
limited extent, and could almost count upon my fingers the particular 
plants for which such a danger is most to be feared. In no part 
of the world has agriculture been carried to a higher piteh of perfec- 
tion than in the British Islands; in no part have the open lands been 
more completely brought under cultivation; yet we know that under 
these adverse cireumstances not more than two or three species, at most, 
have become extinet, although many have become extremely rare, and only 
maintain themselves in situations offering peculiar advantages. The 
Killarney fern, Trichomanes radicans, Sw., has often been reported as 
extinet, yet scarcely a year passes without some new station being disco- 
vered, or some of the old stations proving reproductive. Asplenium 
