296 A NATURALIST IN THE PACIFIC CHAP. 



Linn. Soc. i. 1857; Trans. Linn. Soc. Bot. vi. 1903; Trans. N.Z. 

 Instit. xx. 1887). 



When speaking of the genus in Hawaii (page 275), mention 

 was made of the inter-island dispersal of the fruits of one of 

 the species by the native mountain-goose, Bernicla sandwicensis. 

 We learn from Sir W. Buller's History of the Birds of New 

 Zealand that when the Coprosma is in fruit the Swamp-Hens 

 (Porphyrio melanotus) come out to feed on it. These birds, 

 he says, are capable of prolonged flight ; and I chance to have 

 beside me a cutting from the Field of July 9, 1904, in which 

 " Hy. S." refers to a Black-backed Porphyrio that was captured 

 in 1876 four hundred miles off the coast of New Zealand. This 

 genus, which is widely dispersed in the tropics, the birds being 

 commonly known as Sultanas, Blue Gallinules, Purple Water- 

 Hens, &c., has probably been a very important factor in the 

 dispersal of plants, especially in connection with insular floras. 

 The birds live on a variety of food. The Messrs. Layard 

 observed that Porphyrio vitiensis, which abounds in the swamps 

 of New Caledonia, fed on maize, yams, &c. (Ibis, 1882) ; whilst 

 in the stomach of a bird of the same genus shot in the Rewa 

 swamps in Fiji I found a number of the stony fruits of Scleria, 

 a genus of the Cyperaceae. According to Mr. Wiglesworth, each 

 region in the South Pacific has its own species of Porphyrio. 

 There is one in the Tahitian Islands, and another common to 

 Fiji, Tonga, and Samoa ; whilst New Caledonia and the New 

 Hebrides have their species (" Aves Polynesian "). However, it is 

 evident that the power of dispersing seeds from group to group is 

 not quite suspended, since, as we learn from Sir W. Buller, the 

 New Zealand species, above named as partial to Coprosma drupes, 

 is distributed over Tasmania and Australia, and reaches also Niue 

 and New Caledonia ; whilst the Messrs. Layard evidently re- 

 garded one species as common to Fiji and New Caledonia. 



It is doubtless to birds of this description that we owe some of 

 the specific connections of Coprosma between groups of the Western 

 Pacific. That the dispersal of the species over distant regions was 

 recently in active operation is shown by the close affinity, according 

 to Dr. Stapf, of two species growing on the summit of Kinabalu, the 

 Bornean mountain, with certain species from New Zealand and 

 South-east Australia. Other Rubiaceous species, like Nertera 

 depressa, possessing Coprosma-like fruits and fitted for the same 

 mode of dispersal, link the heights of Kinabalu with the flora of 

 high southern latitudes. 



