The same principle is seen in the naturalisation of plants through man's agency in foreign lands.

It might have been expected that the plants which would succeed in becoming naturalised in any land would generally have been closely allied to the indigenes; for these are commonly looked at as specially created and adapted for their own country.

It might also, perhaps, have been expected that naturalised plants would have belonged to a few groups more especially adapted to certain stations in their new homes.

But the case is very different; and Alph.