Cockayne — Plants of Chatham Island. 301 



var. chathamicum, Cyathodes robusta, Pteris esculenta, Olearia 

 chathamica, and a form of Goprosma propinqua, this latter 

 being a most remarkable plant. As usually seen in Chatham 

 Island it is the principal constituent of one part of the swamp 

 formation ; but here, if the species be the same, it is a pros- 

 trate shrub with long, trailing, slender branches, which in 

 places send down adventitious roots into the rock-crevices. 

 The whole plant is flattened close against the rock ; indeed, it 

 bears no resemblance at all to the erect bushy swamp plant. 

 In certain of the bogs also what I took to be the same form of 

 this species of Goprosma assumes a trailing habit not unlike 

 the rock form just described. The Muhleubeckia mentioned 

 above was growing over the Goprosma, and to some extent 

 they would mutually protect one another from the wind. 

 How far this peculiar adaptation to the rock mode of life is 

 fixed, or if it is merely the effect of wind, &c, and is not 

 hereditary, I cannot say. The plants secured for testing this 

 question unfortunately died. 



It is on the cliffs of the south coast that the richest rock 

 vegetation of Chatham Island is to be found. Here a good 

 deal of accumulated vegetable matter and soil in places, great 

 unevenness of surface, and a south aspect promoting moisture, 

 with much soakage from the wet tableland, have given far 

 more favourable conditions for vegetation, with the conse- 

 quence that the greater part of the coast cliffs are clothed 

 with a beautiful green mantle. This covering is closely re- 

 lated to the tableland forest, but, owing partly to the greater 

 amount of light which can penetrate the vegetation, some of 

 the other plants of the tableland are abundant, notably 

 Phormium tenax and Olearia chathamica. 



Effect of Introduced Animals on the Plant-covering.* 



As I have suggested when speaking of the aborigines, very 

 little change would be wrought in the vegetation of the island 

 by either Moriori or Maori. They would have little object in 

 setting fire to large tracts of country; and, even in case of such 

 being burnt, there would be neither the foreign plant nor 

 animal factor to cause a marked change in the reproduced 

 vegetation. Even at the present time it is almost impossible 

 to discriminate between a piece of bog vegetation which has 

 been burnt many years ago and a piece of the primitive 

 formation. It may therefore be assumed that, to all intents 

 and purposes, the plant-covering of the island at the time of 

 the advent of the missionaries was precisely as it had been for 



* In connection with this, and with the effect of burning on the 

 vegetation of New Zealand, the interesting paper of Canon Walsh may 

 be studied (53). 



