i*6 A NATURALIST IN THE PACIFIC chap. 



o 



we are not called upon to connect them in their origin with 

 M. citrifolia, the wide-ranging species of tropical beaches. 



The fact of the dispersal of certain inland species of the genus 

 over large areas of the tropics, such as in the case of Morinda 

 umbellata through tropical Asia and Malaya, and M. Forsteri in 

 the Pacific, is indeed sufficient proof that these inland plants are 

 independent of any littoral species in the Pacific and possess their 

 own means of distribution. Though the genus, comprising at least 

 forty species, is mainly confined to the Old World, there are a few 

 species in America ; but M. citrifolia, the familiar beach species 

 of the Old World and the Pacific, is not indigenous there, and, as 

 far as I can gather, all the American species belong inland. Facts 

 of distribution of this nature negative the possibility that the 

 Pacific islands have received their inland species of Morinda 

 through the intervention of the far-ranging littoral plant. 



As respecting Calophyllum, which is represented all over the 

 tropical South Pacific by the wide-ranging C. inophyllum and by 

 a tree of the inland forests found also in Malaya and in Ceylon 

 (C. spectabile), there are, apart from questions of affinity, grave 

 objections against the derivation of the same inland species from 

 the coast species all over this area. The fruits of the two inland 

 species of Fiji, C. spectabile and C. burmanni, have sappy outer 

 coverings and are quite suited for dispersal by fruit-pigeons. As 

 observed in Chapter II. and Note 9, they have limited floating 

 capacities and their dispersal by birds is necessary to explain their 

 distribution. Since the timber is greatly valued by the Polynesians, 

 it is not unlikely, however, that those islanders have assisted in the 

 distribution of the inland species. It is not possible to do more 

 than touch on this subject here ; but it may be inferred that the 

 history of Calophyllum in the Pacific has not been one that would 

 warrant our regarding the inland trees as derivatives of a coast 

 species. 



There are other genera of this section where, for reasons of a 

 different character, there is no cause for assuming that the inland 

 species are derived from the coast species, or vice versa. Thus, in 

 Fiji, Casuarina equisetifolia, a widely distributed species of the 

 Old World, occurs at the coast and in the scantily wooded plains 

 behind ; while C. nodiflora, a New Caledonian species, finds its 

 home in the lower forests. There are many endemic species in 

 Australia and New Caledonia ; and we are not called on to con- 

 nect together these two species in Fiji. In the same way we are 

 not under any obligation in the case of the numerous inland species 



