DCP-LETT-3904

# From John Scott   6 January 1863

## January 6th 1863.

Sir,

I send off by train to-night a small box with three plants of P. Scotica and three of P. farinosa.1 I am sorry that I cannot get any more for you at present, but if I can possibly do so in the course of the ensuing spring; you may depend upon receiving them! On one of the plants of P. Scotica, you will observe a few capsules. Perhaps they may not contain many perfect seeds being the produce of late autumn flowers, in cold, damp weather. 〈You〉 will, however, see by these withered and attached 〈f〉lowers 〈    〉 dimorphic condition.2 I have not had an 〈two lines destroyed〉 seen an approach to the dimorphic 〈    〉. I have 〈not had〉 〈an opp〉ortunity of examining it!

I also send in the box with 〈    〉 flowers of the Gongora atropurpurea, which I think 〈will〉 interest you, unless you have already examined it. I believe your remarks on Acropera luteola are equally applicable to it〈.〉 I find the genitalia of Gongora atropurpurea very similar to those of A. luteola according to your description.3 But all my attempts to fertilise it have as yet been unsuccessful. I have never succeeded in inserting a pollen-mass into the stigmatic cavity. It is decidedly more contracted than the majority of those I have examined of A. Loddigesii. 4 In the latter there are usually a few flowers sufficiently open to permit a partial insertion of a pollen-mass; and so it appears to be with A. luteola though in a still less degree; as I observe you had to allow them to shrink a little, and even then rarely succeeded.5 I am now applying viscous matter from other orchids to stigmatic cavity of G. atropurpurea, and thus attaching its pollen-mass, in the hope of thus effecting its fertilisation. This will also aid in preventing the desiccation of the pollen-masses, which takes place ve〈ry r〉apidly in the hot, dry atmosphere where the plant is;6 and thus favours the independent production and protrusion of the pollen-tubes. I may be wrong in entertaining this hope, yet from the success attending the experiments on Acropera, in one of which the pollen mass, scarcely—if at all—penetrated stigmatic cavity,7 I am anxious to to give it a fair test. This opinion, is furthermore supported by the following experiment which seems to show 〈that〉 the pollen tubes may penetrate the column independent of the stigmatic 〈    〉. Having lately observed Dr Hooker’s experiments on the fertilisation 〈of〉 Meconopsis after the stigma had been cut off,8 I 〈three words destroyed

Amongst 〈others〉 I have tried 〈three words destroyed〉 Max〈illaria〉 〈  〉stii; with the latter I have 〈three words destroyed〉 of the former, at present gives fair indications, 〈    〉 〈I〉 believe some of my experiments at your suggestion 〈    〉 then by applying pollen-mass to the rostellum, now promise to be successful. This will be somewhat strange, in considering how much longer the period is before indications of its being effected are given by this mode in comparison with the normal.9

I have been making various random experiments of late on the fertilisation of distinct genera, for the purpose of elucidating in part, your view, “of sterility not being a special endowment’:10 Among many failures, I really believe I have succeeded in fertilising the Stanhopea oculata, with Lælia anceps. 11 I will state my grounds for this hope. There were three flowers experiment〈ed〉 upon one self-impregnated, the other two with pollen from Lælia. the other flowers on the raceme, I did not operate upon. Now in the latter as soon as the perianth drooped, the ovary and labellum quickly followed, first exhibiting a general flaccidity, then becoming dry and shrivelled. Those impregnated, on the other hand, exhibited no such signs, but are still fresh. The ovaries, are swelling, certainly very slowly. Nevertheless the two hybrid products, are still equally as large as the self-impregnated; and they were all experimented upon on the same day, viz; the 13 th Dec. Whether they ever reach maturity or not, they are evidently affected by the pollen of Lælia, otherwise they would have withered long ere this, as is invariably the case with the unfertilised ovaries of Stanhopea. Should they not reach maturity, I will if you wish transmit the ovaries for examination; otherwise—and I have much faith in its being so—I will try if I can possibly get the seeds to germinate; as they certainly would be most anomalous products. By the way, in talking of hybridisation, I will have the so-called Bryanthus erectus in flower shortly, and I intend testing its capabilities for fertilisation. I am aware of Mr. Anderson’s failures, but there is no harm in again attempting it.12 I will also re-cross its parents, and see if I can succeed in raising anything from them. Perhaps I may thus out which was the male and which the female, of the Bryanthus, as I suppose it is not known, and the raiser is now long dead.13 I will be glad if you suggest to me any experiments on these points, that you think would be of interest.

The seed capsule of Acropera is now pretty large—2$\frac{3}{4}$ inches long, by 1$\frac{1}{2}$ inches in circumference.14 I am sorry that those for comparison should be so far behind it. I expected to have a few capsules of a Maxillaria for comparison, but not one of them set; and so it was with the Oncidium ornithorynchum, although I impregnated many flowers of the latter, not a single capsule set. I have now succeeded in fertilising the latter, however, by applying pollen from Oncidium sphacelatum.15 I do not lay much stress on this experiment yet, as my former failures may be owing to uncongenial conditions; but, as further opportunities present themselves, I will carefully attend to them. This far, however, I may safely say, that we have at least an instance, of equal—if not higher susceptibility to others than own pollen. I am determined to devote in future a little more attention to the Orchids. I think curious results may be derived from them.16 I am only sorry that I have not a better collection to experiment upon; for we are indeed poor, and not only in them, but in the majority of the florists favourites. We are very differently situate here in this respect than Kew. Thus first to take the few things you have directed my attention to, I have only at present the Primulas.17 I am now, however, promised from a friend, plants of peloric Antirrhinums and Columbines,18 and likewise Verbascums—one species at least with its varieties, perhaps I may yet get others.19 Do you know anything of the two varieties of Maize, Gartner experimented upon? If I asked you in my last this question about the Verbascum, it was the Maize I intended.20

I remain | Sir, | Yours very respectfully | John Scott.

I am unfortunately perfectly ignorant of the staminal conditions of our Melastomads.28 we have indeed very few of them in the Gardens here. But if the few that we have present any differences, I will attend to them when they again flower.

J. S.

The Primulas being all very weak it would not be advisable to plant them in the garden at present—they had better be kept in pots till spring. It is difficult to get strong plants of Scotica, especially it does not thrive long under cultivation.29 I am sorry that I had no stronger to send you at present. Such as they are you will please to accept in slight acknowledgement of your kindness to me.

J. Scott

## CD annotations

1.1 I send … examining it! 1.9] crossed pencil
2.4 But all … A. Loddigesii. 2.7] double scored red crayon
2.11 applying viscous … this hope. 4.5] crossed blue crayon
5.7 as my former … own pollen. 5.10] scored pencil
Top of letter: ‘Primula | Gongora | Pollen tubes | [Laelia] [left brace added] | Generic crosses | Bryanthus | Acropera | Oncidium | *Maize I know | nothing [left brace added] | Personal details | Melastomas | Sports [circled]’ pencil del pencil

## CD note:

Gongora atropurpurea. Jan 8th 63. Bot. Garden Edinburgh. Labellum astonishing—elongated whenever arched over— viscid [added] disc much larger than in Acropera, to which evidently closely allied.— No movement of depression— *Mouth of stigma [underl red crayon] contracted (see J. Scott)—but viscid within in $\frac{1}{2}$ <ro>tten flower— In *a fresh [underl red crayon] a quantity of this *viscid fluid exuding [underl red crayon] from mouth <    > stigma— Ovarium very [thin] <    > put in spirits to examine ovarium & utriculi—

Gongora [red crayon, circled red crayon] | *He cut open at [illeg] & [fertilised it] [red crayon]

## Footnotes

1
In his letter of 17 December [1862] (Correspondence vol. 10), Scott promised to send CD specimens of Primula farinosa and P. scotica (bird’s-eye primrose and Scottish primrose); CD had been trying to acquire specimens of P. farinosa since 1861, as part of his examination of dimorphism in Primula (see Correspondence vol. 9, letter to Daniel Oliver, 11 September [1861], and Correspondence vol. 10, letter from Daniel Oliver, 10 April 1862).
2
See Correspondence vol. 10, letter from John Scott, 6 December [1862]. Primula scotica is not dimorphic; in a paper detailing his work on Primula, communicated by CD to the Linnean Society on 5 February 1864, Scott described the native plant, P. scotica, as ‘an indigenous illustration of the “non-dimorphic” structure’ in which any variability of stamen length was matched by the style length (Scott 1864a, p. 82).
3
CD described Acropera as the ‘opprobrium’ of his work on orchids, as all the parts seemed ‘determinately contrived’ so that the plant should never be pollinated (Orchids, p. 203); he inferred that A. luteola was dioecious, and that the specimen he examined was male (Orchids, pp. 208–9). In his letter of 11 November 1862 (Correspondence vol. 10), Scott informed CD of his own experiments on a closely allied plant, A. loddigesii; after achieving pollination in two out of six flowers of a raceme, Scott suggested that these species were those in which some of the flowers were male, but others were ‘truly hermaphrodite’. When CD thanked Scott for his letter, he wrote: ‘Your fact has surprised me greatly, & has alarmed me not a little’ (see Correspondence vol. 10, letter to John Scott, 12 November [1862]). Scott subsequently offered to send the ovary of A. loddigesii to CD and to continue experimenting on Acropera (see Correspondence vol. 10, letter from John Scott, 15 November [1862]). See also Correspondence vol. 10, letter to John Scott, 19 November [1862], letter from John Scott, [20 November – 2 December 1862], and n. 4, below. See CD note, above, in which he records his observations of the Gongora specimen sent by Scott.
4
Scott had successfully pollinated Acropera where CD had failed (see Orchids, pp. 205–6); by inserting only a portion of a stipe with the pollinia attached, Scott found that the pollinia then adhered to the mouth of the stigmatic chamber (see Correspondence vol. 10, letter from John Scott, 11 November 1862). See ‘Fertilization of orchids’, p. 153 (Collected papers 2: 150), and Orchids 2d ed., p. 169; see also Correspondence vol. 9, letter to J. D. Hooker, 18 [December 1861]. Acropera loddigesii is now synonymous with G. galeata (Bailey and Bailey 1976).
5
See Orchids, pp. 205–6.
6
Gongora atropurpurea is native to the tropical Americas (Bailey and Bailey 1976). Scott and CD had discussed the importance to successful pollination of viscid matter on the mouth of the stigmatic cavity (see Correspondence vol. 10, letter from John Scott, 11 November 1862, and letters to John Scott, 12 November [1862] and 19 November [1862]).
7
In his letter of 11 November 1862 (Correspondence vol. 10), Scott described his success in pollinating Acropera loddigesii (see also n. 4, above).
8
Scott refers to J. D. Hooker 1854a, in which Hooker described pollinating the ovules directly after cutting off the stigma in several plants of the Papaveraceae (poppies), including Meconopsis. See letter from John Scott, [1–11] April [1863].
9
In his letter to John Scott, 3 December [1862] (Correspondence vol. 10), CD suggested placing a pollen mass directly on the rostellum (the modified stigma of one of the three carpels); under natural conditions, the pollen enters the stigma of one of the two pistils. See also ibid., letter to Asa Gray, 26[–7] November [1862].
10
Scott refers to chapter 8 of Origin (pp. 245–78), in which CD argued against the view that the function of sterility was to prevent the ‘confusion of all organic forms’. In Origin, p. 245, CD expressed his hope to show that sterility was not a ‘specially acquired or endowed quality’, but was ‘incidental on other acquired differences’. See also Correspondence vol. 10, Appendix VI.
11
See Correspondence vol. 10, letter to John Scott, 19 December [1862], for CD’s interest in the ‘relation of well-marked, but undoubted varieties in fertilising each other’. He encouraged Scott to continue this type of experiment, of which the cross of Stanhopea and Laelia was an example. See also ibid., letters from John Scott, 6 December [1862] and 17 December [1862].
12
In his letter of 26–7 January 1863, Isaac Anderson-Henry described a successful cross that yielded the hybrid Bryanthus erectus. Scott later reported that, having crossed Rhododendron chamaecistus and Menziesia empetrifolia, both members of the Ericaceae (heaths), to produce B. erectus, he ‘repeatedly failed’ in setting seed with its own pollen, or the pollen of either parent (Scott 1864c, pp. 199–200 n.).
13
The Edinburgh nurseryman James Cunningham, who died in 1851, was the first to cross Phyllodoce (Menziesia) caerulea and Rhodothamnus chamaecistus to produce the hybrid Bryanthus erectus (Gardeners’ Chronicle, 1 November 1851, p. 695).
14
Scott had promised to send CD the Acropera seed capsule when fully ripened for dissection, along with the seed capsule of another orchid species for comparison (see Correspondence vol. 10, letters from John Scott, 15 November [1862] and [20 November – 2 December 1862]). See also n. 3, above.
15
Scott described this and further experiments with the two Oncidium orchid species in Scott 1863a, pp. 547–8, and Scott 1864b.
16
In his letter to Scott of 19 December [1862] (Correspondence vol. 10), CD had suggested that Scott might undertake crossing experiments with a variety of species. In pollinating plants with their own pollen and with pollen from other varieties and species, Scott, like CD, hoped to answer Thomas Henry Huxley’s objections to natural selection (T. H. Huxley 1863b, p. 107). See letter from John Scott, 21 May [1863] and nn. 10–11.
17
With encouragement from CD (see Correspondence vol. 10, letter to John Scott, 3 December [1862]), Scott later published a paper on dimorphism in Primula (Scott 1864a). There is a copy of Scott 1864a in the Darwin Pamphlet Collection–CUL.
18
In his letter of 19 December [1862] (see Correspondence vol. 10), CD suggested that Scott experiment with peloric flowers.
19
In his letters to Scott of 11 December [1862] and 19 December [1862] (Correspondence vol. 10), CD suggested that Scott experiment with maize and Verbascum (see n. 20, below). Scott later published a paper on several species and varieties of Verbascum (Scott 1867), as well as a paper on Zea mays (Scott 1863b).
20
See Correspondence vol. 10, letter from John Scott, 17 December [1862]. In his letters to Scott of 11 December [1862] and 19 December [1862] (ibid.), CD suggested that Scott repeat the experiments conducted by Karl Friedrich von G¨artner on the fertility of varieties of Verbascum and maize (G¨artner 1844 and 1849), and referred him to his abstract of G¨artner’s work on these plants in Origin, pp. 269–71. The ‘two varieties of maize’ referred to by Scott were a dwarf variety with yellow seeds and a tall variety with red seeds. When these varieties were artificially crossed by G¨artner, only a few seeds were produced. However, the hybrid plants raised from this seed were ‘perfectly fertile’; therefore, as CD pointed out, these two varieties could not be considered ‘specifically distinct’ (Origin, p. 270).
21
James McNab was curator of the Royal Botanic Garden, Edinburgh (R. Desmond 1994). CD was interested in the fertility of abnormal flowers like Begonia frigida, which produced male and female flowers on the same inflorescence. He had acquired a specimen from the Royal Botanic Gardens, Kew (see Correspondence vol. 10, letter to J. D. Hooker, 12 [December 1862], and letter from J. D. Hooker, [14 December 1862]). In his letter to Scott of 19 December [1862] (Correspondence vol. 10), CD mentioned that his Begonia plant was unlikely to set its seeds, and so suggested that Scott investigate the fertility of ‘any monster flower’, particularly Celosia.
22
In his letter to Scott of 19 December [1862] (Correspondence vol. 10), CD offered ‘pecuniary assistance’ with purchases for any experiments Scott conducted at CD’s request.
23
An obituary in the Transactions of the Botanical Society [of Edinburgh] 14 (1883): 160–1, states that Scott’s father was a tenant farmer, his family occupying the same farm for a century.
24
Scott became an orphan at the age of 4. He was brought up by an aunt, and educated at a parish school until he became an apprentice gardener at the age of 14 (Transactions of the Botanical Society [of Edinburgh] 14 (1883): 160).
25
John Hutton Balfour was regius keeper of the Royal Botanic Garden, Edinburgh (DNB).
26
At a meeting of the committee of the Agri-horticultural Society of Madras on 12 March 1862, it was decided to re-engage Robert N. Brown as superintendent of its gardens for a period of three years (Shaw 1877, p. 46).
27
In 1864, Scott became head of the herbarium at the botanic garden in Calcutta (Transactions of the Botanical Society [of Edinburgh] 14 (1883): 160–1).
28
CD was interested in dimorphism in Melastomataceae (see letter to Hugh Falconer, 5 [and 6] January [1863] and n. 22). In his letter to John Scott, 11 December [1862] (Correspondence vol. 10), CD wrote that despite his hard work at seeking the meaning of the ‘two sets of very different stamens’, he was ‘shamefully beaten’.
29
See n. 1, above; the specimens sent to CD by Scott did not thrive (see letter to Daniel Oliver, 20 [February 1863], and letter to John Scott, 24 March [1863]).

## Letter details

Letter no.
DCP-LETT-3904
From
Scott, John
To
Darwin, C. R.
Sent from
unstated
Source of text
DAR 177: 81, 83
Physical description
6pp, †

## Summary

Sends Primula scotica and P. farinosa.

So far cannot fertilise Gongora atropurpurea although it is similar to Acropera luteola.

Experimenting on intergeneric hybrids to test CD’s view that sterility is not a special endowment.

Scott’s personal history.

Acropera capsule grows.

Plans for experiments CD has suggested on Primula, peloric Antirrhinum, and Verbascum.

Aware of Anderson-Henry’s failures.

Through kindness of J. H. Balfour and James McNab, enjoys facilities for research. JS is in charge of the propagating department. Balfour almost engaged him to be superintendent of the Madras Horticultural Garden.