Chap. XII.] MEAiJS OP DISPERSAL. 14S 



sion of 137 days. It deserves notice that certain orders 

 were far more injured than others: nine Leguminosae 

 were tried, and, with one exception, they resisted the 

 salt-water badly; seven species of the allied orders, Hy- 

 drophyllaceae and Polemoniaceae, were all killed by a 

 month's immersion. For convenience' sake I chiefly 

 tried small seeds without the capsule 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 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 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 94 plants with ripe fruit, and to place 

 them on sea- water. The majority sank rapidly, but 

 some which, whilst green, floated for a 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 germinated; an 

 asparagus-plant with ripe berries floated for 33 days, 

 when dried it floated for 85 days, and the seeds after- 

 wards germinated; the ripe seeds of Helosciadium sank 

 in two days, when dried they floated for above 90 days, 

 and afterwards germinated. Altogether, out of the 94 

 dried plants, 18 floated for above 38 days; and some of 

 the 18 floated for a very much longer period. So that 

 as 14 kinds of seeds germinated after an immersion of 

 38 days; and as -^ distinct species with ripe fruit (but 

 not all the same species as in the foregoing experiment) 

 floated, after being dried, for above 38 days, we may 



