386 A NATURALIST IN THE PACIFIC chap. 



plant ; and its berries are well fitted for promoting its dispersal by 

 frugivorous birds. 



I was familiar with Fagraea berteriana both in the Solomon 

 Islands and in Fiji ; and in the last-named locality I especially 

 studied it from the standpoint of dispersal. All over the South 

 Pacific, whether in the Solomon Islands, in Fiji, in Rarotonga, or in 

 Tahiti, this tree, though thriving also in the lower levels, especially 

 frequents rocky scantily vegetated or open-wooded hill-tops and 

 crests up to 2,000 or 2,500 feet above the sea. In the rich alluvial 

 soil of the Rewa delta in Fiji it attains a height of 25 or 30 feet or 

 more, whilst in the poor, dry soil of the " talasinga " plains in this 

 group it is much dwarfed, and often does not exceed 10 feet, and 

 may be only 6 feet high. It is in these "talasinga," or "sun- 

 burnt,"' plains of Fiji, especially in the Mbua province of Vanua 

 Levu, that the tree, although dwarfed, seems most at home. Here 

 it flowers and fruits abundantly whilst associated with Acacia, 

 Casuarina, and Pandanus trees, and it is in such dry localities that 

 this tree reflects in its choice of station the behaviour of different 

 species of the genus in the Malay Peninsula, where they grow in 

 open heath-country and sometimes on sandy heaths (Ridley in 

 Trans. Linn. Soc. Bot., iii, 1888-94). The fruits and seeds of F. 

 berteriana have little or no capacity for dispersal by currents. On 

 the Fijian plains the berries partially wither and rot on the tree. In 

 the western part of its area this tree almost comes in touch with 

 the Asiatic species, F. obovata, that ranges from India and 

 Ceylon to the Malayan region, a species that must be indebted to 

 frugivorous birds for its wide distribution. 



The Euphorbiaceous genus BiSCHOFFiA seems to offer another 

 example of polymorphism in a wide-ranging species. Following 

 Drake del Castillo, I take the genus as including only a single 

 species, B. Javanica, a tree distributed over tropical Asia, Malaya, 

 and Polynesia as far east as Tahiti. The variable character of the 

 species is indicated by the different views held by the several 

 botanists who have discussed the South Pacific species. Whilst it 

 is a common forest-tree in Indo-Malaya, it affects in the Pacific 

 islands the open-wooded districts of the lower levels, and it is not 

 uncommon on the dry " talasinga'" plains of Fiji. The fruits and 

 seeds displayed in my experiments little or no capacity for dispersal 

 by currents ; nor do these dryish berries, with seeds four or five 

 millimetres long, seem to be especially attractive for fruit-eating 

 birds ; and it is likely that the same birds that distribute Macaranga 

 seeds also disperse those of this genus. The tree bears the same 



