424 A NATURALIST IN THE PACIFIC chap. 



of some insect pest introduced since Cook's time or from the use of 

 the timber for fire-wood by the aborigines. 



Serianthes myriadenia 



This is a striking looking Acacia-hke tree that might have been 

 fitly discussed in the chapter on the enigmas of the Leguminosae. 

 Only four or five species are named in the Index Kewensis, of 

 which one occurs in Malacca and in the Philippines, a second in 

 New Caledonia, a third in Fiji, and the fourth, S. myriadenia, over 

 the South Pacific groups of Fiji, Tonga, and Tahiti. Reinecke 

 does not include the genus in the Samoan flora ; and it is merely 

 assigned to that group by Seemann on the authority of Mr. 

 Pritchard, the British Consul in Fiji. Though common in the 

 forests of the larger islands of Fiji, S. myriadenia is most at home 

 on the banks of the estuaries, usually behind the mangrove belt, 

 but not beyond tidal influence. The peculiar species, S. vitiensis, 

 I found on the banks of the estuary of the Mbua River in Vanua 

 Levu, the locality from which Gray described it. According to the 

 French botanists, S. myriadenia, in Tahiti, ranges from near the sea 

 to an elevation of 800 metres. The Fijian name of the trees is 

 " Vaivai," the name also of Leucaena Forsteri, and of some other 

 introduced trees of the Acacia habit. The Tahitians apply the 

 same name in the form of " Faifai " to S. myriadenia. 



The Fijians value the trees on account of the wood ; but unless 

 the Polynesians were in the habit of transporting the seeds of their 

 numerous timber trees, which is most unlikely, it seems at first 

 sight useless to look to man's agency for an explanation of the 

 wide dispersal of a tree like S. myriadenia in the South Pacific. 

 The tough, woody, indehiscent pods, from i\ to 4 inches long, 

 floated in my sea-water experiments in the case of both S. myria- 

 denia and S. vitiensis between seven and twenty-five days, after 

 drying for some months. The seeds, about two-thirds of an inch 

 (17 mm.) in length, are only freed by the decay of the fallen pod, 

 and have no buoyancy. The agency of birds is evidently excluded ; 

 and it is, therefore, to the currents that we must make our final 

 appeal ; but their powers of dispersing the species appear quite 

 insufficient to explain the occurrence of these trees in Tahiti. 

 Perhaps, as in the case of Calophyllum spectabile, another Poly- 

 nesian timber-tree found in Tahiti (see p. 136), man and the 

 currents have worked together. 



