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
Footnotes
Bibliography
Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 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
- ALS 12pp †
Please cite as
Darwin Correspondence Project, “Letter no. 10928,” accessed on 29 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-10928.xml