156 • Transactions. 



New Zealand, may possibly be identical with. Polynesian forms. Melicytus 

 ramiflorus occurs in Norfolk Island, New Zealand, and Eua (Tonga Group). 

 Coprosma acutijolia is endemic. 



In view of the distribution of the arborescent forest-plants of Sunday 

 Island, it follows that the forest as a formation is peculiar, contains some 

 Norfolk Island and New Zealand forms, but most probably h.as greatest 

 affinities with forest formations in certain of the islands of Polynesia. 

 Mr. Cheeseman records (3 ; p. 267) that in Rarotonga Metrosideros villosa 

 and Ascarina lanceolata gxow in company. 



{d.) Dispersal. 



Ocean-currents have probably been the means of transporting to the 

 Kermadec Islands the seeds of a large number of the plants now found 

 there. The nature of the material cast up on the shores of Sunday Island 

 points to the south or south-west as the direction from which the strongest 

 and most frequent reach the group. 



Several kaiiri {Agathis australis, Salisb.) logs, some bearing brands of 

 New Zealand firms, are lying on the shores of Sunday Island, and on the 

 north, coast is a balk of Oregon pine supposed to have formed part of the 

 cargo of the " Elingamite," wrecked on the Three Kings Islands in 1903. 

 Again, during the months of July to October, 1908, when strong westerly 

 winds prevailed, a large amount of seaweed was cast up in Denham Bay. 

 Mr. R. M. Laing, M.A., B.Sc, has supplied me with the following names 

 of algae collected by me on the beaches on Sunday Island : — 



UUrvillcBa antarctica, Hormosira Banksii, 



Carpophyllum maschalocarpum, Zonaria Turneri. 



All the specimens appeared to have come long distances, some having 

 small barnacles (Lepas) attached, and I do not consider any of the above 

 species are to be found living in Sunday Island waters. According to Mr. 

 Laing, they are all New Zealand and south-east- Australian forms. 



It is evident that a strong ocean-current flows from New Zealand in a 

 north-easterly direction ; and this, in my opinion, is sufficient to account 

 for the preponderance of New Zealand forms in the flora of the Kermadec 

 Islands. 



Seeds attached to logs or trees would have a greater chance of crossing 

 wide spaces of ocean and arriving in a fit state for germinating than if they 

 merely floated on the surface of the water. Forest-plants especially would 

 rely on this mode of transportation. Of nineteen kinds of seeds experi- 

 mented on, I found two only floated for any length of time in salt water. 

 These were Ipomcea pes caprce and Canavalia ohtusijolia, two shore-plants 

 widely distributed in tropical regions. 



The large proportion of sporiferous plants, amounting to one-third of 

 the flora, is suggestive of air-currents being an important factor in stocking 

 remote oceanic islands with plants. It is a significant fact, too, that Metro- 

 sideros villosa, which produces an abundance of very light seeds, is widely 

 distributed in Polynesia, and reaches some of the most distant and isolated 

 islets. This plant is the principal tree on Sunday Island. 



Birds have possibly assisted the migration of a number of plants to 

 the Kermadec s. The tui {Prosthemadera novce zealandicB), a fruit -eating 

 bird, is very common on Sunday Island ; and a pigeon was once found 

 there, but has since been exterminated by cats introduced by the settlers 

 who from time to time have made their home on Sunday Island. 



