XXVII LIMNANTHEMUM 



397 



focus into the continents of America and Eurasia. It is also to be 

 doubted whether even in the tropics there has been much over-sea 

 dispersal of Limnanthemum without the aid of man, and reasons 

 will be given for the belief that probably in Fiji, in the New 

 Hebrides, and in New Caledonia the seeds of the first plants were 

 unintentionally introduced by the aborigines. 



Following Bentham we may regard the species of the Western 

 Pacific Islands as a form of the wide-ranging Limnanthemum 

 indicum. These plants in Fiji do not play the part in river- 

 vegetation that they do in the temperate regions, as for instance 

 in the Upper Thames. They are not common except in places, 

 and seem to be chiefly confined to Viti Levu, particularly to ponds 

 in the Rewa delta, where their rdle is that of an Indian tank plant. 

 In the Rewa delta they may be sometimes seen thriving in brackish 

 water having a density of i'005. 



Looking at the mode of dispersal to which the Limnanthemums 

 owe their existence in the Western Pacific, we cannot disregard, 

 especially in Fiji, the possibility of the seeds having been uninten- 

 tionally transported by the natives when they carried in their 

 migrations their edible tubers, such as Colocasia antiquorum, 

 Alocasia indica, and Cyrtosperma edulis, that are cultivated in wet 

 places. It is in the ponds around which these plants grow that the 

 Limnanthemums thrive. The Chinese, with their peculiar methods 

 of cultivation, are now carrying with them strange water-plants 

 over the warmer regions of the globe ; and it would be surprising 

 if the Pacific islanders in their migrations did not do the same. If 

 such an introduction, however, took place, it must have happened 

 before the time of Captain Cook, when the plant was found in New 

 Caledonia. (It may be remarked in this connection that the seeds 

 of the genus will germinate after being kept dry for years. Seeds 

 of the British species which I had kept dry for two and a half 

 years germinated healthily when placed in water.) 



Some years ago I ascertained that the seeds of the British 

 plants were enabled, by means of their fringe of hairs, to attach 

 themselves firmly to the downy plumage of a bird's breast. This 

 could not happen with the Fijian plant as the seeds are naked, and 

 the same may be said of some species described by Gray and 

 Chapman as widely spread over the United States. The seeds of 

 the genus appear quite unsuited for safe transport inside the body 

 of a bird. The Fijians give the plants a variety of names, nearly 

 all of which are associated with the word for a duck, and none of 

 them bear an ancient impress. Thus we find such names as 



