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Darwin Correspondence Project

To Hermann Crüger   25 January [1863]1

Down | Bromley Kent.

Jany 25

Dear Sir.

I hope that you will excuse the liberty I take in begging a favour of you— I have been investigating the manner of fertilization and nature of the pollen in Melastomads, especially in Heterocentron & Monochætum.2 I can find no nectar in these flowers and Prof Asa Gray writes to me that he can find none in the Northern U.S. sps of Rhexia.3 It would take up too much space to explain why I am very anxious to know whether insects visit the flowers of this order.— Mr Bates informs me that in the region of the Amazon’s he hardly ever saw bees or Butterflies sucking the many flowers of the many plants of this order.—4 I dare say some grow in your garden under your superintendence.5 Would you have the kindness to watch them when the weather is fine, occasionally for 5 or 10 minutes & inform me of the result? The species which interest me most are those which have the singular horns or projections to the anther; & four stamens of one colour & shape & four stamens of another colour and shape— The suspicion has crossed me that small insects such as flies or minute sand wasps may penetrate with their proboces or 〈    〉 the horns of the anthers which are filled with fluid  6 If this should prove to be the case, I should very much wish to hear in what position the insect stands on the flower. I do not know whether you have any native species of this order; as such species, or species of allied genera would be best to watch.

Hoping that you will excuse the liberty which I have taken in writing to you & that you will grant me this favour if in your power I Remain | yours 〈    〉

P.S. | If you raise any melastomads from seed in considerable numbers would you be so good as to observe whether on the different individual plants, there is any difference in the position of 〈    〉 pis〈ti〉l or stamens; all the 〈flo〉wers on one plant having the pistil in one position & al〈l〉 the flowers 〈o〉n another plant having the pistil in different position?7

Charles Darwin


The year is established by the relationship between this letter and the letter from Hermann Crüger, 23 February 1863.
For CD’s interest in Melastomataceae, see letter to Hugh Falconer, 5 [and 6] January [1863] and n. 22, and letter to H. W. Bates, 12 January [1863]. For his experimental notes on these two genera, see DAR 205.8.
See letter from Asa Gray, 4 August 1862 (Correspondence vol. 10). Although most members of the Melastomataceae were tropical, Rhexia was a native of North America.
Crüger was director of the botanic garden and government botanist in Trinidad (R. Desmond 1994).
CD was wondering whether insects pollinated the flower when seeking nectar in the horns of the anthers (see letter to Asa Gray, 19 January [1863]). See also letter to Roland Trimen, 16 February [1863] and n. 4, and Orchids, pp. 50–3 and 281–2.
CD began investigating the position of the pistil in the flowers of melastomataceous plants in 1862 (see, for example, Correspondence vol. 10, letter to George Bentham, 3 February [1862], and letter to Asa Gray, 16 February [1862]).


Asks about insect fertilisation of Melastomataceae.

Letter details

Letter no.
Charles Robert Darwin
Hermann Crüger
Sent from
Source of text
DAR 143: 358
Physical description
2pp inc

Please cite as

Darwin Correspondence Project, “Letter no. 3943,” accessed on 19 February 2019,

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