ome casual
acorn or some floating filbert, which might stock my islands with
waving greenery of oaks and hazel bushes. But I gradually discovered,
in the course of a few centuries, that these heavy nuts never floated
securely so far as the outskirts of my little archipelago; and that
consequently no chestnuts, apple trees, beeches, alders, larches, or
pines ever came to diversify my island valleys. The seeds that did
really reach us from time to time belonged rather to one or other of
four special classes. Either they were very small and light, like the
spores of ferns, fungi, and club-mosses; or they were winged and
feathery, like dandelion and thistle-down; or they were the stones of
fruits that are eaten by birds, like rose-hips and hawthorn; or they
were chaffy grains, enclosed in papery scales, like grasses and sedges,
of a kind well adapted to be readily borne on the surface of the water.
In all these ways new plants did really get wafted by slow degrees to
the islands; and if they were of kinds adapted to the climate they grew
and flourished, living down the first growth of ferns and flowerless
herbs in the rich valleys.

The time which it took to people my archipelago with these various
plants was, of course, when judged by your human standards, immensely
long, as often the group received only a single new addition in the
lapse of two or three centuries. But I noticed one very curious result
of this haphazard and lengthy mode of stocking the country: some of the
plants which arrived the earliest, having the coast all clear to
themselves, free from the fierce competition to which they had always
been exposed on the mainland of Europe, began to sport a great deal in
various directions, and being acted upon here by new conditions, soon
assumed under stress of natural selection totally distinct specific
forms. (You see, I have quite mastered your best modern scientific
vocabulary.) For instance, there were at first no insects of any sort
on the islands; and so those plants which in Europe depended for their
fertilisation upon bees or butterflies had here either to adapt
themselves somehow to the wind as a carrier of their pollen or else to
die out for want of crossing. Again, the number of enemies being
reduced to a minimum, these early plants tended to lose various
defences or protections they had acquired on the mainland against slugs
or ants, and so to become different in a corresponding degree from
their Europe