and when stranded, if blown to a favourable spot by an inland gale,
they would germinate.
Subsequently to my experiments, M. Martens tried similar ones, but in a
much better manner, for he placed the seeds in a box in the actual sea,
so that they were alternately wet and exposed to the air like really
floating plants. He tried 98 seeds, mostly different from mine; but he
chose many large fruits and likewise seeds from plants which live near
the sea; and this would have favoured the average length of their
flotation and of their resistance 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 18/98 of
his seeds 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 10/100 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
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
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
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