For convenience sake I chiefly tried small seeds without the
capsules or fruit; and as all of these sank in a few days, they could not
have been floated across wide spaces of the sea, whether or not they were
injured by salt water. Afterwards I tried some larger fruits, capsules,
etc., and some of these floated for a long time. It is well known what a
difference there is in the buoyancy of green and seasoned timber; and it
occurred to me that floods would often wash into the sea dried plants or
branches with seed-capsules or fruit attached to them. Hence I was led to
dry the stems and branches of ninety-four plants with ripe fruit, and to
place them on sea-water. The majority sank quickly, but some which, whilst
green, floated for a very short time, when dried floated much longer; for
instance, ripe hazel-nuts sank immediately, but when dried they floated for
ninety days, and afterwards when planted germinated; an asparagus plant
with ripe berries floated for twenty-three days, when dried it floated for
eighty-five days, and the seeds afterwards germinated: the ripe seeds of
Helosciadium sank in two days, when dried they floated for above ninety
days, and afterwards germinated. Altogether, out of the ninety-four dried
plants, eighteen floated for above twenty-eight days; and some of the
eighteen floated for a very much longer period. So that as 64/87 kinds of
seeds germinated after an immersion of twenty-eight days; and as 18/94
distinct species with ripe fruit (but not all the same species as in the
foregoing experiment) floated, after being dried, for above twenty-eight
days, we may conclude, as far as anything can be inferred from these scanty
facts, that the seeds of 14/100 kinds of plants of any country might be
floated by sea-currents during twenty-eight days, and would retain their
power of germination.
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