326 Means of Dispersal Chap. xii. 



much longer. The result was that \\ of his seeds of different 

 kinds floated for 42 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 ffe 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 which, as Alph. de Candolle has shown, generally have re- 

 stricted 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 enclosed by the roots of an oak about 50 years old, 

 three dicotyledonous plants germinated : I am certain of the accu- 

 racy of this observation. Again, I can show that the carcases 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 : 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 sea-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 safely assume that under such circum- 

 stances their rate of flight would often be 35 miles an hour ; and 

 some authors have given a far higher estimate. I have never seen 

 an instance of nutritious seeds passing through the intestines of 

 a bird ; but hard seeds of fruit pass uninjured through even the 

 digestive organs of a turkey. In the course of two months, I picked 

 up in my garden 12 kinds of seeds, out of the excrement of small 

 birds, and these seemed perfect, and some of them, which were 

 tried, germinated. But the following fact is more important : the 

 crops of birds do not secrete gastric juice, and do not, as I know by 

 trial, injure in the least the germination of seeds ; now, after a bird 



