GEOGRAFHUJAL DISTRIBUTION 151 



out of 87 kinds, 64 germinated after an immersion of 

 28 days, and a few survived an immersion of 187 days. 

 It deserves notice that certain orders were far more in- 

 jured than others: nine Leguminosse were tried, and, with 

 one exception, they resisted the salt water badly; seven 

 species of the allied orders, Hydrophyllacese and Pole- 

 moniacese, 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. Afterward 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 94 

 plants with ripe fruit, and to place them on sea-water. 

 The majority sank quickly, but some which, while 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 afterward 

 when planted germinated; an asparagus-plant with ripe 

 berries floated for 23 days, when dried it floated for 85 

 days, and the seeds afterward germinated; the ripe seeds 

 of Helosciadium sank in two days, when dried they 

 floated for above 90 days, and afterward 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 U kinds of seeds ger- 

 minated after an immersion of 28 days; and as f| distinct 



