PT. I, CH. VII] CONFIRMATION BY PREDICTION G7 



reached the islands before they were cut off. In the case of the 

 Chathams, more particularly, where except New Zealand there 

 IS no other source for the flora than casual arrivals by sea bv 

 currents which also run close to New Zealand, this should be 

 the case. The Kermadecs must have lain fairly near to any in- 

 commg northern current of plants, the Aucklands probably to 

 any southern mvasion, and both these islands therefore may 

 contain plants that were too late, or only just in time, to reach 

 New Zealand at all, but this does not apply to the Chathams 



One will therefore expect, upon the hypothesis of Age and 

 Area that while on the average all the floras of these islands will 

 be old, and therefore widespread, in New Zealand, those plants 

 that reach the Chathams will be the oldest, and most widespread 

 Actual examination soon shows that those plants that reach all 

 three groups, and which are therefore, by hypothesis, about the 

 oldest of all in New Zealand in their own circles of affinity, show 

 the maximum possible range in New Zealand, rangino- "it from 

 end to end. Three of the five are Compositae, including La^eno- 

 phora Forsten, which is endemic to New Zealand and the islands, 

 and the others are Samolus repens and Deyeuxia Forsteri In 

 my papers upon New Zealand I have divided the plants into 

 ten classes by range, instead of the six of the Ceylon flora. The 

 average rarity of a plant in New Zealand, including all the flora 

 is represented by 5-6, and the rarity of these five species is repre- 

 sented by 1. Those plants that reach two groups of islands, 

 which must also, by hypothesis, be very old forms, have a raritv 

 represented by an average of 1-5. Of these plants there are 16 

 species in class 1, 4 in class 2, and a solitary species in class 8, 

 about whose identification there is some doubt, and whose in- 

 clusion brings the average from 1-2, at which it would otherwise 

 stand, to 1-5. 



There are a great many species that reach only one group of 

 islands, and these show on the average less range in New Zealand, 

 but it is very noticeable, th.at just as was predicted above, those 

 of the Chathams show a much greater average range than those 

 of the Kermadecs or Aucklands. The average rarity for a species 

 reaching the Chathams is represented by 1-7, and it would be 

 1-5 were it not that, though there is otherwise no species below 

 class 4, there is one conspicuous exception in class 9, which 

 brings up the average figure. This exception is the Tainui of the 

 Maoris {Pomaderris apetala), which they assert sprang from the 

 rollers or skids of their invading canoe the Tainui, and which 



- IS 

 5—2 



