With respect to plants, it has long been known what enormous ranges many
and even
have, both over continents and to the most remote oceanic islands. This is strikingly
→shown, as remarked by
Alph. de Candolle, in
groups of terrestrial plants, which have
very few aquatic members; for
latter seem immediately to acquire, as if in consequence, a
wide range. I think favourable means of dispersal explain this fact. I have before mentioned that earth
adheres in some quantity to the feet and beaks of birds. Wading birds, which frequent the muddy edges of ponds, if suddenly flushed, would be the most likely to have muddy feet. Birds of this
→I can show, are the greatest wanderers, and
are occasionally found on the most remote and barren islands
the open ocean; they would not be likely to alight on the surface of the sea, so that
dirt
→would
not be washed
→their feet; and when making
land, they would be sure to fly to their natural fresh-water haunts. I do not believe that botanists are aware how charged the mud of ponds is with
I have tried several little experiments, but will here give only the most striking case: I took in February three
of mud from three different points, beneath water, on the edge of a little
this mud when
weighed only
ounces; I kept it covered up in my study for six months, pulling up and counting each plant as it grew; the plants were of many kinds, and were altogether 537 in number; and yet the viscid mud was all contained in a breakfast cup! Considering these facts, I think it would be an inexplicable circumstance if water-birds did not transport the seeds of
→the same fresh-water
plants to
→unstocked ponds and streams, situated at very distant points.
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