36o A NATURALIST IN THE PACIFIC chap. 



(4) The absentees from Tahiti. Amongst the orders are the Mehaccce, the 

 Rhizophorete, and the Conifera?. Amongst the genera, usually those 

 with "stones" or large seeds an inch in size, such as Canarium, 

 Dracontomelon, Myristica, Sterculia, Veitchia, &c. Numerous other 

 absent genera might be named. 

 Fiji. — The Fijian genera 7iot found either in Tahiti or Hawaii. These 

 genera compose about half the Fijian flora, being at least r6o in 

 number. Those especially discussed here are the following :— Hib- 

 bertia, Cananga, Sterculia, Trichospermum, Micromelum, Canarium, 

 Dracontomelon, Begonia, Geissois, Dolicholobium, Lindenia, Myr- 

 mecodia, Hydnophytum, Couthovia, Limnanthemum, Myristica, 

 Elatostema, Ceratophyllum, Gnetum, Veitchia, Rhaphidophora, 

 Lemna, Wolfifia, Scirpodendron. The Conifera^ are dealt with in 

 Chapter XXIV. 



Note appended on Marsilea. 



Having completed our discussion of the general dispersal of 

 tropical genera, chiefly Indo-Malayan, over the Pacific islands, we 

 pass on now to consider the more restricted distribution of non- 

 endemic genera over this region. Here as before we take Hawaii, 

 Tahiti, and Fiji as the three centres of distribution ; and here also 

 we deal with the flowering plants after excluding the orchids, the 

 sedges, the grasses, the mountain-plants, and all plants introduced 

 either by the aborigines or by white men. 



Hawaii. 



After excluding the endemic genera as well as those that 

 are confined to the mountains, we find that this group possesses 

 very few genera that do not occur in the Fijian and Tahitian 

 regions, and fewer still that it owns in common with Tahiti to the 

 exclusion of Fiji. On the other hand, we observe that Fiji 

 possesses a great number of genera, mostly Asiatic in origin, that 

 have not reached Hawaii, and in several cases are not known, from 

 the Tahitian region. These contrasts might have been expected, 

 since the Pacific islands have in later ages been mainly stocked 

 from the Asiatic side of the Pacific, the principal route lying 

 through the Fijian region. 



As far as the flora of the lower levels (below 4,000 feet) is con- 

 cerned, Hawaii only possesses a portion of that which Y\]\ has 

 derived from the Old World, chiefly through Malaya. Although, 

 as will be shown below, there is a noticeable contribution from 

 America, it is very far from counterbalancing the loss which 

 the Hawaiian flora has sustained in comparison with Fiji through 



