314 Tr ansae tions. — Bo tan y . 



slight, which distinguish the forms of the Chatharns from 

 those of New Zealand, would be a matter of high biological 

 interest, but one which is hardly possible in the present state 

 of knowledge regarding the plants. Judging by previous 

 experience, species of the Chatharns supposed to be endemic 

 may be eventually shown to exist in other parts of the New 

 Zealand biological area" when its botany is more fully in- 

 vestigated ; while unrecorded species of local distribution 

 may very possibly be discovered in the Chatham group. 

 So far as genera are concerned, the Chatham Islands possess 

 only one endemic genus, Myosotidium. Taking next the 

 species of Buchanan's list (3), omitting a few the occur- 

 rence of which appears doubtful and adding others re- 

 corded here and elsewhere (37, 39, 40, 41) since its publi- 

 cation, there are about 166 species and distinct varieties of 

 flowering-plants and fifty-one of vascular cryptogams in the 

 Chatham Islands, giving a total of 217, t of which about thirty- 

 one — i.e., 14 per cent. — are considered by me to be endemic, 

 while one, Leucopogon (Styphylea) richei, is, according to Baron 

 Von Mueller, identical with an Australian species. All the 

 remainder occur in some part or other of the New Zealand 

 region ; indeed, with the exception of Rhopalostylis batteri(?), 

 Myrsine chathamica, and Pratia arenaria, they are all to be 

 met with in New Zealand proper. But many of the endemic 

 species are so very closely related to New Zealand forms 

 that it will always be a matter of opinion whether such are 

 at best varieties, and not species at all. 



From the above it may be seen clearly that there is little 

 difference so far as species are concerned between the Chat- 

 ham Islands and New Zealand, and, if the differences be- 

 tween related plants be taken as a measure of the length 

 of time since they deviated from a parent stock, it seems 

 right to consider the flora of the Chatharns as a recent offset 

 from that of New Zealand. 



As to how the New Zealand plants made their way to the 

 Chatharns in the first instance geology teaches us that New 

 Zealand at one time extended very much further to the east 

 than at present, and that it is not unlikely that there was 

 actual land-connection between the two groups of islands 

 (33, p. 177), or if not land, then merely a narrow piece of 

 sea across which the plants could easily migrate by means of 

 birds, wind, and the other agencies discussed by Hemsley (28). 

 Even if the ocean barrier had always been as wide as at 

 present it seems quite possible that plants could find their 



* Lepyrodia traversii, Hymenanthera chathamica, and Myrsine chat- 

 hamica were formerly considered endemic. The latter was collected by 

 Mr. G. M. Thomson at the head of Wilson Bay, Stewart Island (50a). 



t Drude gives only sixty-two indigenous phanerogams (17). 



