, be quite
wrong about the plants of Australia (and your facts are, of course,
quite new to me on their highness), but when I read the accounts of the
immense spreading of European plants in Australia, and think of the wool
and corn brought thence to Europe, and not one plant naturalised, I
can hardly avoid the suspicion that Europe beats Australia in its
productions. If many (i.e. more than one or two) Australian plants are
TRULY naturalised in India (N.B. Naturalisation on Indian mountains
hardly quite fair, as mountains are small islands in the land) I must
strike my colours. I should be glad to hear whether what I have written
very obscurely on this point produces ANY effect on you; for I want to
clear my mind, as perhaps I should put a sentence or two in my abstract
on this subject. (70/4. Abstract was Darwin's name for the "Origin"
during parts of 1858 and 1859.)

I have always been willing to strike my colours on former immense tracts
of land in oceans, if any case required it in an eminent degree.
Perhaps yours may be a case, but at present I greatly prefer land in
the Antarctic regions, where now there is only ice and snow, but which
before the Glacial period might well have been clothed by vegetation.
You have thus to invent far less land, and that more central; and aid is
got by floating ice for transporting seed.

I hope I shall not weary you by scribbling my notions at this length.
After writing last to you I began to think that the Malay Land might
have existed through part of the Glacial epoch. Why I at first doubted
was from the difference of existing mammals in different islands;
but many are very close, and some identical in the islands, and I am
constantly deceiving myself from thinking of the little change which
the shells and plants, whilst all co-existing in their own northern
hemisphere, have undergone since the Glacial epoch; but I am convinced
that this is most false reasoning, for the relations of organism to new
organisms, when thrown together, are by far the most important.

When you speak of plants having undergone more change since old
geological periods than animals, are you not rather comparing plants
with higher animals? Think how little some, indeed many, mollusca have
changed. Remember Silurian Nautilus, Lingula and other Brachiopods, and
Nucula, and amongst Echinoderms, the Silurian Asterias, etc.

What you say about lowness of brackish-water plants interests me.
I remember that t