No doubt direct evidence of seeds being carried great distances through the
air is wanted, but I am afraid can hardly be obtained. Yet I feel the
greatest confidence that they are so carried. Take, for instance, the two
peculiar orchids of the Azores (Habenaria sp.) What other mode of transit
is conceivable? The whole subject is one of great difficulty, but I hope
my chapter may call attention to a hitherto neglected factor in the
distribution of plants.

Your references to the Mauritius literature are very interesting, and will
be useful to me; and I again thank you for your valuable remarks.


LETTER 397. TO J.D. HOOKER.

(397/1. The following letters were written to Sir J.D. Hooker when he was
preparing his Address as President of the Geographical Section of the
British Association at its fiftieth meeting, at York. The second letter
(August 12th) refers to an earlier letter of August 6th, published in "Life
and Letters," III., page 246.)

4, Bryanston Street, W., Saturday, 26th [February, 1881].

I should think that you might make a very interesting address on
Geographical Distribution. Could you give a little history of the subject.
I, for one, should like to read such history in petto; but I can see one
very great difficulty--that you yourself ought to figure most prominently
in it; and this you would not do, for you are just the man to treat
yourself in a dishonourable manner. I should very much like to see you
discuss some of Wallace's views, especially his ignoring the all-powerful
effects of the Glacial period with respect to alpine plants. (397/2.