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Darwin Correspondence Project

From Friedrich Hildebrand   10 November 1863


Novbr 10th | 1863

Dear and respected Sir

I must beg your pardon that I have not answered your very kind letter before this, but I was waiting for my paper on Orchids being printed in the Botanische Zeitung to send you a copy;1 I hope that I shall be able to do it in the next days, you will see that it does not contain much more as you know as yet from my last letter.2 And now let me thank you that you have taken so much pain to get my paper printed, I have seen it in the Annals and Mag. of n. hist. and was very glad of it; I feel very much obliged to you.3 I am glad being able to do you a service in publishing my experiments on Linum and Primula, but I can speak only about L. perenne and P. sinensis, beacause my experiments on P. officinalis and elatior were destroyed by childeren in the botanical garden.4 On Linum I spoke a few words on the meeting of German naturalists in Stettin.5

In your paper on Primula you say, that you never placed pollen of the same flower on its own stigma6 but I thought this manner of fertilisation to be of interest too, and I had in this way six unions instead of your four. The result was that the two heteromorphic unions gave most seeds, namely each capsule 43 good seeds on an average; the two homomorphic unions, if the flowers were crossed, gave 18 seeds on an average per capsule, the flowers selffertilised only 13. In the first four unions I got good capsules of every fertilised flower, only in the last two I did not always succeed in the fertilisation.— You see that, though I have counted the seeds, not weighed, I have come to the same results as you.7 But I must say that I cannot agree with you about the pollen of P. sinensis, for I found the pollen grains of the long styled form almost in the same manner differing from that of the short styled as in P. officinalis and elatior; between the small transparent grains of the short-styled form there were only a few of larger seize and opace.—8

Perhaps it will interest you to hear that I have made other experiments to answer the question to what form the descendants of the two forms belong. From seeds that I had got last year by your four unions I got about 60 young plants and these were the interesting results: Of the descendants from long-styled plants fertilised with their own form pollen most, but not all, were again long styled; the short-styled form fertilised with its own-form pollen produced in the greatest part short styled plants; if the short styled form was fertilised with the long-styled or the long styled with the short styled nearly the half of the young plants was short-styled the other half long-styled.—9

Coming to a close I must say that if there is anything, where I can serve you, perhaps with microscopical researches, I should be very glad if you would tell me about it, the winter especially leaves me a great deal of time.

Professor Treviranus wanted me to send you his respects and remembrances.10 Some time ago I heard that you were not quite well but I hope that this letter will find you in good health and I remain most respected Sir | yours | sincerely | Hildebrand


See letter to Friedrich Hildebrand, 28 July [1863]. Hildebrand’s paper on orchids (Hildebrand 1863a) was published in the issues of Botanische Zeitung for 30 October and 6 November 1863; there is an annotated copy of Hildebrand 1863a in the Darwin Pamphlet Collection–CUL.
In his letter to CD of 16 July 1863, Hildebrand included an English abstract of Hildebrand 1863a.
At Hildebrand’s request, CD asked Daniel Oliver and Joseph Dalton Hooker about the possibility of publishing an abbreviated version of Hildebrand 1863a in an English journal (see n. 2, above, letter to Daniel Oliver, 18 July [1863], and letter to J. D. Hooker, 22 July [1863]). Hildebrand’s paper, entitled ‘On the impregnation in orchids as a proof of the two different effects of the pollen’ appeared in the September 1863 issue of Annals and Magazine of Natural History (Hildebrand 1863b). See letter to Friedrich Hildebrand, 28 July [1863].
See letter to Friedrich Hildebrand, 28 July [1863]. Hildebrand published his experiments on Linum and Primula sinensis in Hildebrand 1864.
Hildebrand’s statement that he had confirmed CD’s results with Linum perenne by experiment is briefly reported in Amtlicher Bericht über die 38. Versammlung Deutscher Naturforscher und Ärzte in Stettin im September 1863.
In ‘Dimorphic condition in Primula, pp. 86–8 (Collected papers 2: 54–6), CD described experiments that tested the potency of the pollen of the different forms of Primula veris, P. sinensis, and P. auricula. To avoid the possible negative effects of close interbreeding, CD never placed the pollen of a flower on its own stigma. Hildebrand published his observations in Hildebrand 1864; CD commented on Hildebrand’s results in ‘Illegitimate offspring of dimorphic and trimorphic plants’, pp. 411 n. and 413 n., and in Forms of flowers, pp. 40–3, 192 n., and 217 n.
While CD observed little difference in the pollen grains of the two forms of P. sinensis (‘Dimorphic condition in Primula, pp. 80–1 (Collected papers 2: 48)), Hildebrand wrote (Hildebrand 1864a, p. 2) that the pollen grains of the long-styled plants were smaller and more transparent than those pollen of the short-styled form. In this letter, Hildebrand writes that it was the short-styled plants that yielded small and transparent pollen grains. By ‘seize and opace’ Hildebrand presumably meant size and opacity. CD noted the published information in Forms of flowers, p. 38 n. See also ‘Illegitimate offspring of dimorphic and trimorphic plants’, p. 416.
For Hildebrand’s data, see Hildebrand 1864, pp. 4–5.
Ludolph Christian Treviranus had been Hildebrand’s teacher in Bonn (Correns 1916, p. 29).


Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

Correns, C. 1916. Friedrich Hildebrand. Berichte der deutschen botanischen Gesellschaft 34 (pt 2): 28–49.

‘Dimorphic condition in Primula’: On the two forms, or dimorphic condition, in the species of Primula, and on their remarkable sexual relations. By Charles Darwin. [Read 21 November 1861.] Journal of the Proceedings of the Linnean Society (Botany) 6 (1862): 77–96. [Collected papers 2: 45–63.]

Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.

Hildebrand, Friedrich. 1864. Experimente über den Dimorphismus von Linum perenne und Primula sinensis. Botanische Zeitung 22: 1–5.

‘Illegitimate offspring of dimorphic and trimorphic plants’: On the character and hybrid-like nature of the offspring from the illegitimate unions of dimorphic and trimorphic plants. By Charles Darwin. [Read 20 February 1868.] Journal of the Linnean Society of London (Botany) 10 (1869): 393–437.


Pleased CD has had his [FH’s] orchid paper published [Ann. & Mag. Nat. Hist. 3d ser. 12 (1863): 169–74].

Extension of CD’s Primula heterostyly work.

Letter details

Letter no.
Friedrich Hermann Gustav (Friedrich) Hildebrand
Charles Robert Darwin
Sent from
Source of text
DAR 166: 201
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4337,” accessed on 20 October 2020,

Also published in The Correspondence of Charles Darwin, vol. 11