h, 1868.

...Now I want to beg for assistance for the new edition of "Origin."
Nageli himself urges that plants offer many morphological differences,
which from being of no service cannot have been selected, and which he
accounts for by an innate principle of progressive development. (697/1.
Nageli's "Enstehung und Begriff der Naturhistorischen Art." An address
delivered at the public session of the Royal Academy of Sciences of
Munich, March 28th, 1865; published by the Academy. Darwin's copy is the
2nd edition; it bears signs, in the pencilled notes on the margins, of
having been read with interest. Much of it was translated for him by a
German lady, whose version lies with the original among his pamphlets.
At page 27 Nageli writes: "It is remarkable that the useful adaptations
which Darwin brings forward in the case of animals, and which may be
discovered in numbers among plants, are exclusively of a physiological
kind, that they always show the formation or transformation of an
organ to a special function. I do not know among plants a morphological
modification which can be explained on utilitarian principles." Opposite
this passage Darwin has written "a very good objection": but Nageli's
sentence seems to us to be of the nature of a truism, for it is clear
that any structure whose evolution can be believed to have come about
by Natural Selection must have a function, and the case falls into
the physiological category. The various meanings given to the term
morphological makes another difficulty. Nageli cannot use it in the
sense of "structural"--in which sense it is often applied, since that
would mean that no plant structures have a utilitarian origin. The
essence of morphology (in the better and more precise sense) is descent;
thus we say that a pollen-grain is morphologically a microspore. And
this very example serves to show the falseness of Nageli's view, since
a pollen-grain is an adaptation to aerial as opposed to aquatic
fertilisation. In the 5th edition of the "Origin," 1869, page 151,
Darwin discusses Nageli's essay, confining himself to the simpler
statement that there are many structural characters in plants to which
we cannot assign uses. See Volume I., Letter 207.) I find old notes
about this difficulty; but I have hitherto slurred it over. Nageli gives
as instances the alternate and spiral arrangement of leaves, and the
arrangement of the cells in the tissues. Would you not consider as a
morphological