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Darwin Correspondence Project

From John Scott   12 April 1877

Bankipore

12th. April/ 77

Dear Sir,

I had hoped to get down to Calcutta ere this and get some papers, which I have there, looked over, for my notes on Lagerstrœmia (as I have none here) but I am detained and will be, I find for a week or two longer.1 I have heard from Dr. King, but only to the effect that he can make nothing whatever of the specimens in the herbarium.2 I was surprised at this but he has lately sent me a few of the specimens of L. indica and elegans, all truly worthless as I find for your purpose.3 Not a single flower has an entire pistil or stamen, indeed scarcely a trace of them: the work doubtless of the herbarium boys, who are employed brushing mouldy specimens during the rainy season.

In so far as I recollect the species I particularly referred to was L. elegans Wall. I have never observed it produce a single seed in our gardens or in those of Calcutta, though it is very generally grown as an ornamental shrub. Moreover, it is everywhere associated with L. indica, of which I believe it is now regarded as a variety.4 L. indica the normal var. with red flowers is fairly fertile in the Calcutta gardens if I recollect aright, but in gardens here I have rarely seen a single seed vessel on it, and that never containing more than two good seeds.

I find only one form in the gardens here (Bankipore), I enclose flowers; I am sorry I could not get more of them.5

Lafoensia Vandelliana and Duabanga Sonneratiaoides, are peculiarly variable from season to season in their fertility.6 I have notes somewhere on them, but I cannot lay my hands on them. I have no doubt however the variability is due to the flowers being visited or neglected by insects. The frequency of flower-visiting insects in our fields and gardens varies much from season to season. I think much more so than in temperate climates.

I have this season been struck with the numbers of two small bees which have haunted the flowers of a Litchi (Nephelium Litchi) in my garden here. The result of this is that a very large of fruits are twin: this I assure you is most exceptional, indeed I never in the Calcutta gardens observed it. of the normally 2-celled ovary one only attains maturity. Different specimens bear varying proportions of male and hermaphrodite flowers.7

I made as I wrote you before a series of intercrosses &c as you suggested with our vars. of the opium poppy.8 However, I have now learned, that the real secret of the varieties not intercrossing is wholly due to the absence of insects at the period of their flowering; i.e the months of December, January & February. I have just had a provoking illustration of this. Last season, I had seeds of Turkey, Spanish, Italian and French opium poppy, sent me. I had five crops of each, but they did not come into flower until well on in March, and thus afforded a very late crop. Being much occupied with other work I did not observe that insects were haunting the flowers, but I was much astonished to find that the vars. were hopelessly intercrossed: a red-flowered French var. being the prepotent as evidenced by the preponderance of flowers approaching it in form and colour. I have thus attended particularly to them during the flowering period, and I find various species of Bees greedily feeding on their pollen. This is so much the case that in looking over the flowers an hour or so after the first expansion in the morning, you can scarcely find a trace of pollen. Indeed they scarcely leave a trace of it on the stigma, and I am sure that this season anyhow, the plants can be but very sparingly fertile. I shall not fail to let you know the results when I gather the crop. As I told you before, I never observed insects affecting our local vars. of poppy which flower early. It is indeed very remarkable that, the winds (often very strong during their flowering period to not effect general intercrossing of the vars. This no doubt the explanation of the apparent permanency of the vars. remarked on by M. Jourdan.—9

I have just finished, and having finally copied a rather lengthy paper on Sap Circulation, in which I have shown it I think satisfactorily to be mainly due to barometric pressure.10 I have also giving I think good and sufficient reason for the rejection of the theory of a descending, elaborated sap. In it I have given illustrations of those vessels in the poppy on which the peculiar rythmical motion of the milk-sap depends.

I remain | Dear Sir | yours truly | John Scott

CD annotations

4.2 I have … climates. 4.6] crossed blue crayon; ‘April 1877’ added red crayon
4.6 temperate climates.] highlighted red crayon
6.1 I made as I wrote you] opening square bracket red crayon; marked with cross red crayon
6.1 I made … February. 6.4] ‘April 12 77’ added red crayon
6.6 but they … the flowers, 6.9] scored pencil
7.1 I have … depends. 7.6] crossed blue crayon

Footnotes

Scott, who was curator of the Royal Botanic Garden, Calcutta (now Kolkata), had been seconded in 1872 to the opium department and was in charge of the experimental gardens at Deegah and Meetapore (Digha and Mithapur, Patna) near Bankipore (Bankipur, Patna; Scott 1876). As part of his research for Forms of flowers, CD had asked Scott for more information on species of Lagerstroemia, a genus of the family Lythraceae (see Correspondence vol. 24, letter to John Scott, 15 December 1876).
George King was superintendent of the Royal Botanic Garden, Calcutta.
In a letter of 21 July 1865 (Correspondence vol. 13), Scott had reported that Lagerstroemia indica (crape myrtle) and L. elegans (see n. 4, below) were sterile in the Royal Botanic Garden, Calcutta.
Lagerstroemia elegans Wall. is a synonym of L. indica, and considered to be a variety of the latter with paler flowers.
The enclosure has not been found. In his letter to Scott of 15 December 1876 (Correspondence vol. 24), CD had asked for flowers of each form in order to measure the size of the pollen-grains. CD described the extreme variability in the length of the stamens and the uniformity in size of the pollen-grains of Lagerstroemia indica, and cited Scott’s observations, in Forms of flowers, pp. 167–8.
Lafoensia vandelliana and Duabanga sonneratioides (a synonym of D. grandiflora) are also members of the family Lythraceae.
Nephelium litchi is a synonym of Litchi chinensis (lychee). Scott probably observed members of Trigona, a genus of small stingless bees (see Heard 1999, p. 195). Lychees produce functionally female flowers with fully developed pistils and non-dehiscent anthers, and two types of functionally male flowers, some with rudimentary pistils and others with developed but non-functional pistils (Sedgley and Griffin 1989, p. 66). Scott probably mistook some flowers for hermaphrodite.
The opium poppy is Papaver somniferum. CD had suggested crossing experiments for Scott to perform on varieties of P. somniferum to determine whether they were, in fact, species (see Correspondence vol. 24, letter to John Scott, 1 July 1876).
For Scott’s earlier comments on crossing in varieties of poppy, see the letter from John Scott, 24 February 1877. Alexis Jordan had argued that there was a group of poppies similar to Papaver dubium that ought to be classed as separate species because they bred true even when grown together for several years (Jordan 1860, pp. 467–8).
Scott’s work on sap circulation has not been identified.

Bibliography

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

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

Heard, Tim A. 1999. The role of stingless bees in crop pollination. Annual Review of Entomology 44: 183–206.

Jordan, Alexis. 1860. Diagnoses d’espèces nouvelles ou méconnues pour servir de matériaux à une flore de France réformée. Annales de la Société Linnéenne de Lyon 7: 373–518.

Scott, John. 1876. Annual report on the experimental poppy gardens at Deegah and Meetapore for the season ending 31st May 1875. Calcutta: Bengal Secretariat Press.

Summary

Comments on various species of Lagerstroemia.

In the series of opium poppy intercrosses made at CD’s suggestion, JS has learned that the reason they failed to intercross was the absence of insects at the period of their flowering.

Letter details

Letter no.
DCP-LETT-10928
From
John Scott
To
Charles Robert Darwin
Sent from
Bankipore
Source of text
DAR 47: 207–9
Physical description
12pp †

Please cite as

Darwin Correspondence Project, “Letter no. 10928,” accessed on 18 January 2022, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-10928.xml

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