24 A NATURALIST IN THE PACIFIC chap. 



Fiji, on the Pacific coast of South America, and in Sicily, and with 

 the same results. 



Since the elaboration of my notes was begun in 1900, Dr. 

 Sernander, the Swedish botanist, has published (i 901) his work in 

 Swedish on the Dispersal-biology of the Scandinavian plant-world, 

 in which the seed-drift of river, pond, and sea is exhaustively 

 treated. Although this author has dealt with plant-dispersal from 

 a somewhat different standpoint, I have perused his pages with the 

 keenest interest and with great profit, having gone over much of 

 the same ground with respect to the seed-drift of ponds and rivers. 

 Yet the introductory remarks to my paper in Science Gossip in 1895 

 are as apposite now as they were then, and the reader will, I trust, 

 pardon my reproducing them. 



" By following up the path of inquiry that is concerned with the 

 flotation of seeds and seedvessels, we are guided into other fields of 

 research that give promise of interesting discoveries in connection 

 with plant-life. We are led in the first place to consider the ques- 

 tion of utility, and to ask whether the buoyancy of the seed or 

 fruit has been a matter of moment in the history of the species. 

 Nature is ever engaged in telling off the plants to their various 

 stations. She places the yellow iris at the river's side and assigns 

 to the blue iris its home in a shady wood. Under her direction 

 the common alder thrives at the water's edge, whilst its fellow 

 species live on the mountain slope. These and similar operations 

 are carried on daily around us, and we know but little of the where- 

 fore and the how. We are induced, therefore, to inquire whether 

 by pursuing the line of investigation above indicated we may be 

 able to get a glimpse at the methods adopted by Nature in select- 

 ing stations for plants." 



I possess the results, which are given in Note 10, of buoyancy 

 experim^ents and observations on the seeds and seedvessels of 

 about 320 British flowering plants belonging to about 65 families. 

 Of these about 260 are included in my own results, the data for the 

 rest being obtained from the writings of Darwin, Martins, Thuret, 

 Kolpin Ravn, and Sernander. In the great proportion of cases, 

 240, or 75 per cent, sinking took place at once or within a week ; 

 whilst 80, or 25 per cent, floated for a longer period, usually a month 

 or more ; and about 60, or nearly 20 per cent., floated for several 

 months. It is to this last small group that belong the seeds or 

 seedvessels that float through the winter in our ponds and rivers. 



If the grasses had been properly represented, the grains of which 

 possess as a rule but little buoyancy, except through air-bubbles 



