MEANS OF DISPERSAL. SGI 



He twed ninety-eight seeds, mostly different from mine, 

 but lie chose many large fruits, and likewise seeds, from 

 plants which live near the sea; and this would have favored 

 both the average length of their flotation and their resist- 

 ance to the injurious action of the salt water. On the other 

 hand, he did not previously dry the plants or branches with 

 the fruit; and this, as we have seen, would have caused 

 some of them to have floated much longer. The result was 

 that J | of his seeds of different kinds floated for forty -two 

 days, and were then capable of germination. But I do not 

 doubt that plants exposed to the waves would float for a 

 less time than those protected from violent movement as in 

 our experiments. Therefore, it would perhaps be safer to 

 assume that the seeds of about ^°q 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 facts of 

 the larger fruits often floating longer than the small, is 

 interesting; as plants with large seeds or fruit which, as 

 Alph. de Candolle has shown, generally have restricted 

 ranges, could hardly be transported by any other means. 



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 that when irregularly shaped stones are 

 embedded in the roots of trees, small parcels of earth are 

 frequently enclosed in their interstices and behind them, so 

 perfectly that not a particle could be washed away during 

 the longest transport : out of one small portion of earth 

 thus completely inclosed by the roots of an oak about fifty 

 years old, three dicotyledonous plants germinated: I am 

 certain of the accuracy of this observation. Again, I can 

 show that the carcasses of birds, when floating on the sea 

 sometimes escape being immediately devoured : and many 

 kinds of seeds in the crops of floating birds long retain their 

 vitality : pease 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 sea- 

 water for thirty 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 safety 



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