has been very striking; but only, as far as
I can yet judge, with exotic plants which do not get freely crossed by
insects in this country. In some of these cases it is really a wonderful
physiological fact to see the difference of growth in the plants
produced from self-fertilised and crossed seeds, both produced by the
same parent-plant; the pollen which has been used for the cross having
been taken from a distinct plant that grew in the same flower-pot. Many
thanks for the dimorphic Rubiaceous plant. Three of your Plumbagos have
germinated, but not as yet any of the Lobelias. Have you ever thought of
publishing a work which might contain miscellaneous observations on all
branches of Natural History, with a short description of the country and
of any excursions which you might take? I feel certain that you might
make a very valuable and interesting book, for every one of your
letters is so full of good observations. Such books, for instance Bates'
"Travels on the Amazons," are very popular in England. I will give your
obliging offer about Brazilian plants to Dr. Hooker, who was to have
come here to-day, but has failed. He is an excellent good fellow, as
well as naturalist. He has lately published a pamphlet, which I think
you would like to read; and I will try and get a copy and send you.
(676/2. Sir J.D. Hooker's lecture on Insular Floras, given before
the British Association in August, 1866, is doubtless referred to. It
appeared in the "Gardeners' Chronicle," and was published as a pamphlet
in January, 1867. This fact helps to fix the date of the present
letter.)

LETTER 677. TO F. MULLER.

(677/1. The following refers to the curious case of Eschscholtzia
described in "Cross and Self-Fertilisation," pages 343-4. The offspring
of English plants after growing for two generations in Brazil became
self-sterile, while the offspring of Brazilian plants became partly
self-fertile in England.)

January 30th [1868].

...The flowers of Eschscholtzia when crossed with pollen from a distinct
plant produced 91 per cent. of capsules; when self-fertilised the
flowers produced only 66 per cent. of capsules. An equal number of
crossed and self-fertilised capsules contained seed by weight in the
proportion of 100 to 71. Nevertheless, the self-fertilised flowers
produced an abundance of seed. I enclose a few crossed seeds in hopes
that you will raise a plant, cover it with a net, and observe whether it
is self-fertile; at the s