Chap. XI. 
MEANS OF DISPERSAL. 
359 
out of 87 kinds, 64 germinated after an immersion of 
28 days, and a few survived an immersion of 137 days. 
For convenience’ sake I chiefly tried small seeds, 
without the capsule or fruit; and as all of these sank 
in a few days, they cpuld not be floated across wide 
spaces of the sea, whether or not they were injured by 
the salt-water. Afterwards I tried some larger fruits, 
capsules, &c., 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 might wash down plants or branches, 
and that these might be dried on the banks, and then 
by a fresh rise in the stream be washed into the sea. 
Hence I was led to dry stems and branches of 94 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 90 days, and afterwards 
when planted they germinated; an asparagus plant 
with ripe berries floated for 23 days, when dried it 
floated for 85 days, and the seeds afterwards germi¬ 
nated ; the ripe seeds of Helosciadium sank in two days, 
when dried they floated for above 90 days, and after¬ 
wards germinated. Altogether out of the 94 dried 
plants, 18 floated for above 28 days, and some of the 18 
floated for a very much longer period. So that as 
seeds germinated after an immersion of 28 days; and 
as plants with ripe fruit (but not all the same species 
as in the foregoing experiment) floated, after being dried, 
for above 28 days, as far as we may infer anything from 
these scanty facts, we may conclude that the seeds of 
plants of any country might be floated by sea-cur¬ 
rents during 28 days, and would retain their power of 
germination. In Johnston’s Physical Atlas, the average 
