XXI THE AGE OF COMPOSITE 235 



(2) The genera forming the low-level flora of Hawaii 

 below 4,000 or 5,000 feet and composing almost the 

 entire floras of the Fijian and Tahitian regions. Pre- 

 dominantly Indo-Malayan. 



{a) The age of general dispersal over the tropical Pacific, 

 the genera with only peculiar species being first 

 treated, and afterwards those possessing a non- 

 endemic element. 

 (b) The age of local dispersal over the tropical Pacific. 



The First Era of the Flowering Plants, being the 

 Age of the Endemic Genera. 



With the above preliminary remarks I pass on to the next 

 stage in the history of the stocking of these islands with their 

 plants. The age of the ferns and lycopods is left behind, and it 

 is assumed that the next era is mainly indicated by those genera 

 of phanerogams that are now peculiar to their respective groups. 

 In this connection by far the most interesting of the three regions, 

 the Hawaiian, the Tahitian or East Polynesian, and the Fijian, is 

 that of Hawaii, which, as before observed, is distinguished from the 

 groups of the Fijian and Tahitian regions, or, in other words, from 

 all the oceanic archipelagoes of the tropical Pacific, by its large 

 number of endemic genera. 



Peculiar genera of shrubby and arborescent Compositse and of 

 arborescent Lobeliacea form the most striking characteristics of the 

 endemic genera, and therefore of the ancient flora of Hawaii. It is 

 in this connection of singular interest to remark that of the three 

 endemic genera of the Tahitian flora one is an arborescent genus of 

 the Compositae, and the other two are shrubby genera of the 

 Lobeliacese. There are, therefore, indications here of an ancient 

 insular flora of the Pacific, characterised mainly by the prevalence 

 of Compositae and Lobeliaceae. It is, however, remarkable that 

 not only are no endemic genera of these orders known from Fiji or 

 from the adjacent groups of Samoa and Tonga, but that the 

 Lobeliaceae are not represented at all, whilst amongst the Fijian 

 Compositae, with the exception of Lagenophora, the genera display 

 no endemic element as far as the data at my disposal indicate. 



The problem we are brought face to face with is clearly stated 

 by Mr. Hemsley in the Introduction to the Botany of the Chal- 

 lenger Expedition (p. 68). " In Polynesia as elsewhere," he re- 

 marks, " the Compositse more particularly are perplexing to the 



