﻿230 Trcmsactions. — Botany. 



of Otago mosses," and Mr. Buchanan, wlio has paid much attention to the 

 bryology of the South Island, informed me that he had searched for it in vain. 

 It was originally discovered in Auckland by Dr. Knight, and subsequently 

 by Captain Hutton and myself, about four or five years ago. Since that time 

 it has become plentiful by road-sides, walks, and on walls, etc., but has not 

 been found at any great distance from the city. When gi'owing on scoria it 

 usually presents a remarkably dull and depauperated appearance, instead of its 

 normal shining aspect, so that, when not in fruit, it is possible for even a good 

 observer to walk over large patches of the plant without noticing it, but when 

 growing on walls it exhibits the glossy and silvery look from which it dei-ives 

 its trivial name. 



Its evident rarity in the South Island, and the restricted area to which it 

 appears to be confined in the North, together with its rapid local increase 

 during the last four or five years, when considered collectively, are certainly 

 calculated to suggest the idea of its exotic origin ; an idea which is apparently 

 strengthened by the fact of its comparatively recent recognition in the noii;h, 

 and by its exhibiting no departure from the ordinary European type of the 

 plant ; but the slightest examination of these conditions in detail will suffice 

 to show that alone they can afibrd no support to the theory. Other plants, 

 both Phsenogams and Cryptogams, whose nativity here cannot be called in 

 question, occur under exactly similar conditions of abundance in Europe, and 

 rarity in New Zealand ; and if it be further urged that the climatal conditions 

 of these islands would lead us to expect a wide distribution of our plant, the 

 same statement would still apply. I will content myself with citing Hedtoigia 

 ciliata, the rarity of which in the North Island has been already mentioned, as 

 an instance in point. The apparent rapid increase of our plant, as well as its 

 recent recognition in this locality, may be accounted for by the increase of 

 habitats more suitable for its luxuriant growth than the natural scoria, 

 especially if we remember that, from their nature and situation, plants growing 

 upon them are brought prominently into notice. 



But even if this plant exhibited a more rapid increase, extending over a 

 wider area, this could not be taken as evidence of its exotic origin ; for 

 causes attendant upon the progress of settlement have led to the local increase 

 of many plants whose nativity stands unquestioned, but which would be open 

 to suspicion on exactly the same ground, Azolla rubra, M'hich some years 

 ago was stated by Mr. Travers to have increased in the province of Canterbury 

 to such an extent as to impede drainage, affords a marked instance of the 

 local increase of a Cryptogam which is decidedly rare in many districts, 

 Geratodon purpureus, a cosmopolitan moss, has increased largely with the 

 development of settlement in the north, and probably throughout the colony. 

 It is, howevei', a remarkable fact, that, with the exception of certain moulds 



