324 ON THE ORIGIN OF SPECIES 



to the waves would float for a less time than those pro- 

 tected from violent movement as in our experiments. 

 Therefore it would perhaps be safer to assume that the 

 seeds of about ifcfo plants of a flora, after having been 

 dried, could be floated across a space of sea 900 miles 

 in width, and would then germinate. The fact of the 

 larger fruits often floating longer than the small, is 

 interesting ; as plants with large seeds or fruit could 

 hardly be transported by any other means ; and Alph. 

 de Candolle has shown that such plants generally have 

 restricted ranges. 



But seeds may be occasionally transported in another 

 manner. Drift timber is thrown up on most islands, 

 even on those in the midst of the widest oceans ; and 

 the natives of the coral-islands in the Pacific, procure 

 stones for their tools, solely from the roots of drifted 

 trees, these stones being a valuable royal tax. I find 

 on examination, that when irregularly shaped stones 

 are embedded in the roots of trees, small parcels of 

 earth are very frequently enclosed in their interstices 

 and behind them, — so perfectly that not a particle 

 could be washed away in the longest transport : out of 

 one small portion of earth thus completely enclosed by 

 wood in an oak about 50 years old, three dicotyle- 

 donous plants germinated: I am certain of the accu- 

 racy of this observation. Again, I can show that the 

 carcasses of birds, when floating on the sea, sometimes 

 escape being immediately devoured ; and seeds of 

 many kinds in the crops of floating birds long retain 

 their vitality : peas and vetches, for instance, are killed 

 by even a few days' immersion in sea-water ; but some 

 taken out of the crop of a pigeon, which had floated on 

 artificial salt-water for 30 days, to my surprise nearly 

 all germinated. 



Living birds can hardly fail to be highly effective 

 agents in the transportation of seeds. I could give 

 many facts showing how frequently birds of many kinds 

 are blown by gales to vast distances across the ocean. 

 We may I think safely assume that under such circum- 

 stances their rate of flight would often be 35 miles an 



