xxvi METROSIDEROS 341 



named " aalii " in Hawaii, " apiri " in Tahiti, " ake " in Rarotonga, 

 " lala vao " in Samoa, and I may add " usi " or, as Seemann writes 

 it, " wase" in Fiji. 



Looking at these various facts, I am not inclined to exclude 

 altogether any one of the three agencies above discussed ; but I 

 should imagine that, placed in their order of effectiveness, we should 

 have first birds, then the currents, and lastly man. 



METROSIDEROS (Myrtaceae) 



Whilst this genus of trees and shrubs has its home in New 

 Zealand and Australia, there is an extremely variable Polynesian 

 species, Metrosideros polymorpha, ranging over all the volcanic 

 groups of the tropical Pacific, from Fiji to Pitcairn Island and 

 from Hawaii to the Kermadec group, but seemingly only in the 

 Hawaiian group associated with endemic species. According to 

 the Index Kewensis the genus comprises about forty known species, 

 of which two-thirds are confined to New Zealand and Australia in 

 equal proportions ; whilst, among the rest, six species belong to 

 New Caledonia, two to Hawaii, and three to Malaya, and there 

 are solitary species in Chile, Madagascar, and South Africa. 



I will attack the problem connected with the distribution 01 

 the genus through the widely-ranging Polynesian species, Metro- 

 sideros polymorpha. " This genus," wrote Dr. Seemann, " is in a 

 fair way of becoming in Polynesia what Rubusis in Europe. It is 

 very much given to variation, and it is very difficult to find out the 

 limits of the different species." In making these remarks he had 

 this species in view, and his adoption of Gaudichaud's specific name 

 of " polymorpha " to cover almost all the Polynesian forms has been 

 generally followed. Although so widely distributed over the 

 Pacific, it is in the Hawaiian Islands that this tree attains its greatest 

 development, growing gregariously and often forming almost ex- 

 clusively entire forests ; and it is here that it displays the greatest 

 variation. But it was remarked by Seemann, and this was con- 

 firmed by Hillebrand, that almost all the Hawaiian forms occur in 

 the Society or Tahitian Islands. 



In connection with the great variability of Metrosideros 

 polymorpha must be considered its variety of stations and its great 

 range in altitude. Hillebrand describes seven Hawaiian forms of 

 this species, and their various stations and characters are well 

 illustrated in his descriptions. Thus, whilst the trees may attain a 

 height of forty feet in the forests, in elevated exposed situations 



