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Darwin Correspondence Project

From J. D. Hooker   [26 June or 3 July 1856]1


Thursday Nt

Dear Darwin

I can make no story at all out of the N.W. American plants:2 the cases I had in view have all turned up in the Altai, & especially in the Baikal Siberia & Dahuria3, which is a very fertile nook of N. Asia: there are however a considerable number of plants absolutely peculiar to N.W. America, west of the Rocky mountains.4 Various Asiatic & Europæan plants that advance Eastwards to Sitka & the Aleutians but no further East in Am. advance much further North on the two Pacific coasts than they do in the interior of Asia, & were long supposed (by me at any rate) to be foreign to Siberian Asia. I am however writing to Asa Gray & will ask him if he can give any information.5

By the greatest good luck in the world we have two seedlings of the Asiatic Entada, growing side by side with the Azorean, & they are very different species; so that you have no sooner found proof that the West Indian one will travel with unimpaired vitality to the old world, when it turns out that it has not taken advantage of its powers after all.! a beastly disgusting fact, which I hope will give a little more countenance than you will allow to my dogma, that it it is much more difficult so to wash seeds up that they shall grow, than to transport them.

When opening some Aristolochia flowers I find the pollen all escaped & on the stigma before expansion—ditto in some Visca, the buds being firmly closed. 6

A Dr Radlkofer7 tells me that Siebold has proved that some ♀ Bees & Butterflies are sometimes fertile without impregnation;8 is this true?

That paper in Flora to which you allude seems to be very good,9 I am thinking of getting it translated: would it not be much better for the Ray Club to confine its efforts to translating such things & leave it to Societies to publish original monographs, which with proper support the Socs. could do better than the Ray Club. 10

Thomson11 has refound near Calcutta one of the most remarkable anomalies in Geogr: dist: of plants in Aldrovandra, a most singular & curious rare S. Europæan water plant, allied to Drosera, of which a drawing exists at the Calcutta Garden, but for which Griffith,12 Wallich,13 Falconer, Hook fil & Thomson & scores of others have hunted the length & breadth of India for in vain: but which Thomson has found abundantly in a few small ponds about 5 miles from Calcutta, It proves to be absolutely identical with S. European local plants14

CD annotations

crossed pencil
crossed pencil and ink
square brackets added ink
‘labiosa’ added ink
‘No a mistake; is diœcious’ added pencil and ink
crossed ink
‘F. W.’ added brown crayon
Top of first page: ‘ I think I may say this these spot [in circle], at N.W. America & near [’Lake‘ del] Baikal, plants are fd. whereas not fd. in intermediate districts; suits me as well.’ ink; ‘20’15 brown crayon; ‘Aldrovanda’ pencil


The conjectured dates are the two Thursdays between the letters to J. D. Hooker, 22 June [1856] and 5 [July 1856].
See letter to J. D. Hooker, 22 June [1856]. CD was anxious to ascertain whether any of the plants that were found in both Europe and North America could also exist under Arctic or sub-Arctic conditions. He had asked Hooker and Hewett Cottrell Watson (letter from H. C. Watson, 5 June 1856) whether these species were known to range northwards. CD’s point was explained in Natural selection, p. 539, where he attempted to show that the species that are now common to Europe and North America had formerly comprised part of a circumpolar flora that migrated southwards during the glacial period. The case of local species in north-west America, west of the Rocky Mountains, was cited by CD as an example of ‘nests of species’ having been left behind after the flora retreated northwards (Natural selection, p. 540).
The area formerly inhabited by the Dahur cossacks in northern Manchuria.
CD repeated this information in Natural selection, p. 540.
Shortly after receiving this letter, CD wrote on his own account to Asa Gray asking the same question (see letter to Asa Gray, 14 July [1856]).
Hooker was mistaken in his observation of Viscum, which has separate sexes (see CD’s annotations, above, and letter from J. D. Hooker, 10 July 1856).
Ludwig Radlkofer was an authority on both the sexual and asexual reproduction of plants, about which he wrote several books, including Die Befruchtung der Phanerogamen (Leipzig, 1856). In 1857 and 1858 he published studies on parthenogenesis.
A reference to Karl Theodor Ernst von Siebold’s researches on parthenogenesis (Siebold 1856). Siebold overturned Richard Owen’s definition of parthenogenesis (Owen 1849) by showing that the cells from which new organisms developed were true ova and not simply pre-existing ‘germinal’ cells contained within the parent’s body. Siebold demonstrated that these ova were capable of development without fertilisation. See Farley 1982, pp. 100–5.
See letter to T. H. Huxley, 4 May [1856], in which the financial difficulties of the Ray Society were discussed. The society had undertaken to translate and publish some foreign monographs, but most of its publications were original monographs, including both volumes of CD’s Living Cirripedia (1851 and 1854).
Thomas Thomson was superintendent of the Calcutta botanic garden and professor of botany at the Calcutta Medical College. He was co-author with Hooker of the Flora Indica (J. D. Hooker and Thomson 1855).
William Griffith had travelled widely in Bhutan and Assam between 1835 and 1838 before becoming superintendent of the Calcutta botanic garden. He died in 1845.
Nathaniel Wallich had been superintendent of the Calcutta botanic garden before Griffith and had catalogued the plants in the East India Company’s museum in London.
The words ‘absolutely … plants’ were added to the bottom of the page by CD and were presumably copied from the missing part of Hooker’s letter.
The number of CD’s portfolio of notes on the geographical distribution of plants.


Farley, John. 1982. Gametes & spores: ideas about sexual reproduction, 1750–1914. Baltimore and London: The Johns Hopkins University Press.

Natural selection: Charles Darwin’s Natural selection: being the second part of his big species book written from 1856 to 1858. Edited by R. C. Stauffer. Cambridge: Cambridge University Press. 1975.

Siebold, Karl Theodor Ernst von. 1856. Wahre Parthenogenesis bei Schmetterlingen und Bienen. Ein Beitrag zur Fortpflanzungsgeschichte der Thiere. Leipzig. [Vols. 7,8]


Can no longer make out story of NW. American plants; consulting Asa Gray.

Questionable validity of seed-salting experiments.

Aristolochia and Viscum seem to shed pollen before flower opens.

Ray Society should only do translations.

Thomas Thomson in India has rediscovered Aldrovanda, a rare relative of Drosera.

Letter details

Letter no.
Joseph Dalton Hooker
Charles Robert Darwin
Sent from
Source of text
DAR 104: 197
Physical description
inc ††

Please cite as

Darwin Correspondence Project, “Letter no. 1911,” accessed on 18 May 2024,

Also published in The Correspondence of Charles Darwin, vol. 6