282 A NATURALIST IN THE PACIFIC chap. 



growing on the Java mountains. He there shows {Plant-Geography^ 

 i. 14) that species which are epiphytes in the virgin forest become 

 terrestrial plants in the treeless alpine region. This interchange of 

 station, which is exhibited by several other plants, including orchids 

 and ferns, is connected with their xerophilous characteristics, and 

 is given by Schimper as an example of the interchange of physio- 

 logically dry habitats. 



Of the mode of dispersal of Vaccinium by frugivorous birds, 

 much has been written and much will be familiar to my readers. 

 The berries of V. reticulatum are known to be the principal food 

 of the Hawaiian mountain-goose. But probably birds of the grouse 

 family have been the chief agents in distributing the genus over 

 the continents. I have frequently found the fruits in the stomachs 

 of the Black Cock (Tetrao tetrix), the Scotch Grouse (Lagopus 

 scoticus), and the Capercailzie (Tetrao urogallus) ; but the same 

 story comes from all over the northern hemisphere. The Willow 

 Grouse (Lagopus albus), which travels round the globe, is known to 

 feed on them. Hesselman in Sweden and Ekstam in Nova Zembla 

 have especially investigated the dispersal of Vaccinium by Tetrao 

 tetrix and Lagopus (see Sernander, pp. 6, 226) ; and according 

 to Mr. Douglas and others the different species of Tetrao that 

 frequent the subalpine regions of the Rocky Mountains and the 

 uplands of Columbia and North California subsist on Vaccinium 

 fruits. This family is not now represented in the Hawaiian 

 avifauna ; but it is noteworthy, as indicated by the differentiation 

 of the Pacific species of Vaccinium, that dispersal of the genus is 

 there almost suspended except within the region of Eastern 

 Polynesia. It is probable that numerous other birds, except the 

 Hawaiian goose, aided the original dispersal. 



The Mountain Genera with both Endemic and Non-endemic 

 Species. — I pass on now to consider those Hawaiian mountain genera 

 that possess species some of which are confined to the group, 

 whilst others occur in regions outside the islands. They are not 

 many, as may be seen from the table before given, and but few of 

 them are entirely restricted to the high levels, a range in altitude 

 that may be frequently associated with great lateral extension of 

 the genus over different latitudes. Here the agents of dispersal 

 have through some species in each genus preserved a connection 

 with the outer world, though it may be restricted to the limits of 

 the Pacific islands. 



Cyathodes tameiameiae, an Epacridaceous species found also in 

 the uplands of Tahiti, occurs, according to Hillebrand, on all the 



