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Letter 3868

Darwin, C. R. to Scott, John

19 Dec [1862]

    Summary Add

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    JS should be proud of his paper ["Nature of the fern-spore", Edinburgh New. Philos. J. 2d ser. 16 (1862): 209–27].

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    CD has just found that JS's observations on the confluence of two sexes causing variability were independently confirmed by Huxley.

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    CD has always suspected a fundamental difference between buds and ovules.

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    Asks for examples of "bud-variation" or "sports".

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    Asks JS to test germination of pollen on rostellum of Laelia.

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    Offers JS money for experimental supplies, e.g., netting, to keep insects out of flowers.

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    Encloses an outline of crossing experiments with Lythraceae, Primula, Pelargonium, and others, which he feels would be valuable.

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    Note on melastomids.

Transcription

Down Bromley Kent

Dec. 19th

Dear Sir

There is no occasion to thank me; it is simply a pleasure to me to aid (if aid it can be called) anyone who really loves science; & you conferred a great favour on me about Acropera.— You have taken my little criticisms in the spirit in which they were intended. You have reason, in my opinion, to be proud of your paper.— By odd chance reading last night some short Lectures just published by Prof. Huxley, I find your observation, independently arrived at by him, on the confluence of two sexes causing variability.— I must write briefly.— Difference or similarity of buds & ovules is beyond my tether: I have spoken of them in deference to others as identical, but I have always suspected some fundamental difference.

Talking of buds, if you can give me any cases of what Gardeners sometimes call sports, & which I shall call ``bud-variation'' I shall be grateful, as I want to collect all cases like moss—on common rose,—nectarine on Peach.—

I did not at all know about foliage of Begonia.—

I shall be very glad indeed of P. farinosa & Scotica.: if in pots in open ground I suppose they will do???

I can tell you nothing about vars of Verbascum, except that I have in vain tried to get white & yellow vars. of same species.

If Lælia should set (as does not from what you say appear probable) seed-capsules with pollen put on Rostellum: then if you were to examine one specimen & see whether pollen-tubes penetrated Rostellum it wd., I shd. think, suffice.—

In my experiments, I have found net, (such as bit enclosed) distended with hoops or fastened on square frame of sticks, answer perfectly in excluding insects, during flowering season, & not injure fertility of plants. Now there ought to be no false delicacy between us followers of science; if any pecuniary assistance is required to purchase pieces of net & pay for making, nets, grant me the favour to apply to me.— Excuse Brevity, as I am tired. I will append about experiments separately.—

Yours very faithfully | C. Darwin



[Enclosure: 1]

Experiments

To the best of my judgment, no subject is so important in relation to Theoretical Natural Science, in several respects, & likewise in itself deserving investigation; as the effects of changed or unnatural conditions, or of changed structure on the reproductive system.

Under this point of view the relation of well-marked, but undoubted varieties in fertilising each other, requires far more experiments than have been tried.

See in Origin the brief abstract of Gärtner on Verbascum & Zea.—

Mr. W. C. Crocker, lately foreman at Kew & a very good observer is going at my suggestion to work vars of Hollyhocks. Climate wd be too cold, I suppose, for vars. of Tobacco. I began on Cabbage, but immediately stopped from Early shedding of their pollen causes too much trouble. Your knowledge would suggest some.

On same principle it would be well to test peloric flowers, with their own pollen; & with pollen of regular flowers; & try pollen of peloric on regular flowers,—seeds being counted in each case.

I have now got one seedling from many crosses of a peloric Pelargonium by peloric pollen; I have 2 or 3 seedlings from a peloric flower by pollen of regular flower.— I have ordered a peloric Antirrhinum & the peloric Gloxinia, but I much fear I shall never have time to try them.

The Passiflora-cases are truly wonderful, like the Crinum cases (see Origin). I have read in German paper that some varieties of Potatoes (name not given) cannot be fertilised by own pollen, but can by pollen of other vars; well worth trying

Again fertility of any monster flower, which is pretty regularly produced; I have got the wonderful Begonia frigida from Kew, but doubt whether I have heat to set its seeds. If an unmodified Celosia could be got; it would be well to test with the modified Cockscomb. There is a var. of Columbine with simple petals without nectaries &c &c.—

I never could think what to try; but if one could get hold of a long cultivated plant which crossed with a distinct species & yielded a very small number of seed; then it would be highly good to test comparatively the wild parent form & its varying offspring with this third species: for instance if a polyanthus would cross with some species of Primula, then to try a wild cowslip with it.— I believe hardly any Primulas have ever been crossed. If we knew & could get parent of Carnation it would be very good for this end.—

(Any member of the Lythraceæ, raised from seed ought to be well looked after for dimorphism: I have wonderful facts, the result of experiment, on Lythrum salicaria.—



[Enclosure: 2]

Melastomatads.

Have you any species with two sets of stamens widely dissimilar. It would be better not to try Heterocentron roseum(?) or mexicanum(?) with purple flowers—or Monochætum ensiferum; for I have tried many experiments on these with no sure result, but with plain indications that there is something odd about them; for seedlings produced by the two kinds of pollen differed wonderfully in their rate of growth & in setting seed &c—

If you have any such & are inclined to operate; first observe whether the pistil retains the same position from time flower opens till it withers: if it does not move, merely try both pollens & mark capsules. The Counting the seed is awful labour, but I would undertake it. (N.B. in all experiments it is quite necessary to wrap up well each ripe capsules in separate paper.)

If pistil moves, experiment is more troublesome, for both pollens shd. be applied to the stigma at the two ages & positions. I am completely baffled, but I strongly suspect there is something very strange in these Melastomas. There is nothing odd, as I know by trial, in such genera as Centradenia & Rhexia.

    Footnotes Add

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    f1 3868.f1
    The year is established by the relationship to the letter from John Scott, 17 December [1862].
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    f2 3868.f2
    See letter from John Scott, 17 December [1862]. Scott had initiated the correspondence with CD in November when he wrote concerning the sexual forms of the orchid Acropera (see letter from John Scott, 11 November 1862). Earlier in December, CD had arranged for copies of Journal of researches and the third edition of Origin to be sent to Scott (see letters to John Scott, 3 December [1862] and 11 December [1862]).
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    f3 3868.f3
    See letter to John Scott, 11 December [1862], and letter from John Scott, 17 December [1862].
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    f4 3868.f4
    Scott had sent CD a copy of Scott 1862a (see letter from John Scott, 6 December [1862]); it is preserved in the Darwin Pamphlet Collection--CUL.
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    f5 3868.f5
    See Scott 1862a, p. 214, and Huxley 1862, p. 90--2. See also letter from John Scott, 17 December [1862].
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    f6 3868.f6
    CD discussed the resemblances of buds and ovules in chapter 11 of Variation, a chapter he began writing in December 1862 (see n. 7, below). He concluded by stating that the facts he had collected showed in how `close and remarkable' a manner the germ of a fertilised seed and the small cellular mass forming a bud resemble each other in function and in their capacity for variation (Variation 1: 411).
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    f7 3868.f7
    CD began writing a draft of chapter 11 of Variation, `On bud-variation, and on certain anomalous modes of reproduction and variation', on 21 December 1862 (see `Journal' (Correspondence vol. 10, Appendix II)). He cited observations by Scott of this phenomenon in Variation 1: 385.
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    f8 3868.f8
    See letter from John Scott, 17 December [1862] and n. 6.
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    f9 3868.f9
    Scott offerred to send CD specimens of Primula scotica and P. farinosa in his letter of 17 December [1862].
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    f10 3868.f10
    See letter from John Scott, 17 December [1862] and n. 19. Regarding CD's attempts to obtain specimens of Verbascum, see the letter to W. E. Darwin, 4 [July 1862] and n. 4.
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    f11 3868.f11
    See letter from John Scott, 17 December [1862] and n. 20.
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    f12 3868.f12
    See letter to John Scott, 11 December [1862], and letter from John Scott, 17 December [1862].
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    f13 3868.f13
    Origin, pp. 270--1.
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    f14 3868.f14
    See letters from C. W. Crocker, [before 13 March 1862] and 24 November 1862.
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    f15 3868.f15
    CD refers to the possibility of Scott repeating a series of crossing experiments on varieties of the tobacco plant (Nicotiana), which had originally been carried out by Joseph Gottlieb Kölreuter. CD reported Kölreuter's findings in Origin, pp. 271--2, discussing their significance with regard to hybrid sterility.
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    f16 3868.f16
    In DAR 76: 40, there are dated notes from CD's crossing experiments with cabbages in May and June 1862. CD continued to carry out similar experiments with cabbages between 1863 and 1871 (see DAR 76: 41--4 and DAR 78: 139--56); he discussed his findings in Cross and self fertilisation, pp. 98--103.
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    f17 3868.f17
    CD refers to the crossing experiments, begun in May 1862, with the normally sterile peloric flowers of pelargoniums (see letter to Daniel Oliver, 8 June [1862], letter to Asa Gray, 1 July [1862], and letters to M. T. Masters, 8 July [1862] and 24 July [1862]). CD's notes from these experiments are in DAR 51 (ser. 2): 4--9, 12--13. In Variation 2: 70, CD described crossing experiments on peloric flowers of Antirrhinum major; his notes from these experiments, dated 1863--5, are in DAR 51 (ser. 2): 18--23.
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    f18 3868.f18
    Origin, pp. 250--1.
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    f19 3868.f19
    CD refers to an article entitled `German pamphlets on the potato disease, and its remedies', which appeared in the Gardeners' Chronicle and Agricultural Gazette, 21 March 1846, pp. 181--3. The article provided an abstract of Albert 1845, and included the observations noted here in a translation of the appendix, `Upon the regeneration, or profitable propagation of potatoes from seeds', by `Inspector' Tinzmann. CD cited Tinzmann's observations in Variation 2: 137. CD's annotated copy of the Gardeners' Chronicle is in the Cory Library, Cambridge Botanic Garden; he noted the article cited here in his abstract of the journal (DAR 75: 1--12).
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    f20 3868.f20
    See letter to J. D. Hooker, 12 [December 1862], and letter from J. D. Hooker, [14 December 1862].
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    f21 3868.f21
    CD discussed the modified forms of the columbine and the cock's-comb (Celosia cristata) in Variation 1: 365.
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    f22 3868.f22
    In the summer of 1862, CD made extensive crossing experiments with the trimorphic plant, Lythrum salicaria (see letter to Daniel Oliver, 29 [July 1862]); the observational notes from this work are preserved in DAR 27.2. CD's paper, `Three forms of Lythrum salicaria', was read before the Linnean Society of London on 16 June 1864.
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    f23 3868.f23
    CD began to investigate the occurrence of two sets of stamens in the flowers of the Melastomataceae in October 1861, suspecting that the family might exhibit a novel form of dimorphism (see Correspondence vol. 9, letter to J. D. Hooker, 17 November [1861] and n. 14, and this volume, letter to George Bentham, 3 February [1862]). He continued to work on the family throughout 1862 and 1863 without ultimately being able to account for the two sets of stamens (see Cross and self fertilisation, p. 298 n., and ML 2: 292--302). CD's notes from these experiments are in DAR 205.8. CD mentioned his work on the Melastomataceae in his letter to Scott of 11 December [1862], and sought Scott's assistance with his experiments.
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    f24 3868.f24
    CD had begun experimenting with Heterocentron roseum in October 1861; his observational and experimental notes on this species, dated October 1861 -- January 1863, are in DAR 205.8: 45--7, 49--53, 56. He began crossing experiments on Monochaetum ensiferum in February 1862 and continued to work on the species until May 1863 (see DAR 205.8: 22--41). His experimental notes on H. mexicanum, dated June -- October 1862, are in DAR 205.8: 19 v., 54. CD was also seeking to obtain specimens of these genera from their native South America (see letter to J. D. Hooker, 14 [October 1862], and letter from J. D. Hooker, [18 October 1862]).
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    f25 3868.f25
    Having noticed that in Monochaetum ensiferum there were changes over time in the positions of the pistils and stamens, CD had speculated that the pistil might react differently to the two kinds of pollen produced by this species, depending on its age and position (see letter to Asa Gray, 16 February [1862]).
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    f26 3868.f26
    CD's observational and experimental notes on Rhexia glandulosa (dated June and July 1862) and on various species of Centradenia (dated January -- July 1862) are in DAR 205.8: 14--21. In addition, Asa Gray had, at CD's request, supplied him with observations on Rhexia Virginica (see letter from Asa Gray, 4 August 1862).
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