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Letter 4526

Scott, John to Darwin, C. R.

10 June [1864]

    Summary Add

  • +

    Sends Passiflora paper [see 4485].

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    Sends seeds of peloric Antirrhinum crossed by normal form and sends results of his experiments [table of crosses].

Transcription

Denholm

June 10th.

Sir.

I sent off by yesterday's mail my papers of experiments on Passifloras &c. You will judge when you have time to look them over whether or not I have succeeded in drawing them up in such a manner as will admit of your communicating them to the Linn. Soc.

I enclose a packet of seeds of Peloric Antirrhinums crossed by normal form. I also send results of my experiments on these forms&lldots; The self-sterility of peloric in my case is I believe opposed to results of previous experimenters. Wildenow in particular has somewhere stated that he has succeeded in fertilising peloric with own-pollen

My experiments were performed on two vigorous plants: both proved utterly impregnable by own-pollen, though both before & after and at the time of trying experiments with own-pollen, they were readily fertilised by pollen of normal; while the former likewise proved perfectly good on the stigmas of the latter. Further I have found that individual peloric flowers which occasionally occur on otherwise normal form are likewise self-sterile: though both sexual elements prove good when treated reciprocally with normally structured flowers.

I will be glad to hear how results of my experiments agree with yours, should you have made any: if desirable I will give mine in detail.

I am sorry that I have [no] seeds by me, otherwise you should have had them. I gave a quantity of seeds—Primulas—hybrid & pure—of both unions to friend of mine in Edinburgh who takes an interest in these matters & I will hear how they result. I sowed a quantity of the hybrid seeds myself. I am attending particularly to the germinative powers of such. I find that frequently a large per-centage of these seeds though perfectly developed are nevertheless unfit for germination:

I have the honour to remain | Sir | Your obedt. servant | John Scott



[Enclosure: 1]

Unions of Normal and Peloric Anthirrhinums

Comparative fertility

of the pure & cross

unions

Number Number of Total Average of Number of Number pure- cross-

of flowers capsules number seeds per capsules of seeds unions unions

fertilised produced of seeds capsule 1. Normal Anthirrhinum 10. 10. 1264. 126. 20. 2528. 1000. '' by own pollen 2. Normal Anthirrhinum 10. 8. 908. 113. 20. 2270. '' 897. by pollen of Peloric Anthirrhinum (P. No. 1) 3. Normal Anthirrhinum 10. 10. 1097. 110. 20. 2194. '' 867. by pollen of Peloric Anthirrhinum (P. No. 2) 4. Peloric Anthirrhinum 10. 10. 1334. 133. 20. 2668. '' 1055. (P. No. 1) by pollen of Normal Anthirrhinum 5. Peloric Anthirrhinum 10. 10. 1362. 136. 20. 2724. '' 1077. (P. No. 2) by pollen of Normal Anthirrhinum 6. Peloric Anthirrhinum 24. 0. '' '' ' '' (P. No. 1) by own pollen 7. Peloric Anthirrhinum 24. 0. '' '' ' '' (P. No. 2) by own pollen 8. Peloric Anthirrhinum 12. 0. '' '' ' '' (P. No. 1) by pollen Peloric Anthirrhinum (P. No. 2) 9. Peloric Anthirrhinum 12. 0. '' '' '' '' (P. No. 2) by pollen Peloric Anthirrhinum (P. No. 1)

    Footnotes Add

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    f1 4526.f1
    The year is established by the relationship between this letter and the letter from John Scott, 5 May [1864].
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    f2 4526.f2
    At CD's suggestion, Scott had carried out extensive experiments on sterility and hybridity in Passiflora and compared his results with observations of Disemma and Tacsonia (see Correspondence vol. 10, letters from John Scott, [20 November -- 2 December 1862] and 17 December [1862], Correspondence vol. 11, and this volume, letters from John Scott, 19 March 1864 and 28 March 1864 and nn. 16 and 17). Scott's paper was communicated by CD to the Linnean Society, where it was read on 16 June 1864. It was published in the Journal of the Linnean Society of London (Botany) (Scott 1864d). CD's annotated copy of the paper is in the Darwin Pamphlet Collection--CUL.
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    f3 4526.f3
    See enclosure. CD had encouraged Scott to experiment on peloric and normal forms of flowering plants, including Antirrhinum (see letter to J. D. Hooker, [1 April 1864] and n. 4). CD began crossing experiments on the peloric flowers of Antirrhinum majus in 1863 (see Correspondence vol. 11, letter to John Scott, 20 [June 1863], and his notes from these experiments, dated 1863--5, in DAR 51: B18--23). See also letter to J. D. Hooker, [1 April 1864] and n. 4, and letter from John Scott, 20 June [1864] and n. 6.
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    f4 4526.f4
    Scott refers to Carl Ludwig Willdenow. In his letter to Journal of Horticulture, [before 18 June 1861] (Correspondence vol. 9; Collected papers 2: 44), CD had remarked that, while peloric flowers were generally sterile, Willdenow had obtained seeds from a peloric snapdragon, Antirrhinum majus. The publication by Willdenow has not been identified.
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    f5 4526.f5
    CD's experiments with Antirrhinum majus showed the species to be self-fertile when pollinated artificially (see letter from John Scott, 20 June [1864] and n. 6).
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    f6 4526.f6
    Scott's friend in Edinburgh has not been identified.
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    f7 4526.f7
    CD may have asked Scott for hybrid seeds of Primula veris and P. vulgaris in a letter that has not been found; CD had been crossing the two species since 1862 and had recently concluded that the crosses resulted in a hybrid, the common oxlip (see letter to J. D. Hooker, 10 June [1864]). Scott and CD often considered the number, size, and external conditions of seeds, but their germination was the ultimate test of fertility of crosses (see, for example, letter to W. E. Darwin, 14 May [1864] and n. 6, experimental note in DAR 108: 71, and Forms of flowers, p. 59).
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