From Fritz Müller1 19 October 1877
Blumenau, Sa. Catharina, Brazil
19. October 1877.
Verehrter Herr!
Obwohl ich Ihnen kaum etwas mitzutheilen habe, darf ich doch nicht länger mit dem Ausdruck meines herzlichen Dankes zögern für Ihr Buch über die verschiedenen Formen von Blüten, welches mir grosse Freude gemacht hat.2 Es war für mich sehr anregend, im Zusammenhang und mit so vielen werthvollen Zusätzen, all Ihre bewundernswerthen Beobachtungen und Versuche über verschiedengrifflige (heterostyle) Pflanzen zu verfolgen.
You mention (“Different Forms of Flowers,” page 331) the deficiency of glands on the calyx of the cleistogamic flowers of several Malpighiaceæ, suggesting, in accordance with Kerner’s views, that this deficiency may be accounted for by the cleistogamic flowers not requiring any protection from crawling insects.3 Now I have some doubt whether the glands of the calyx of the Malpighiaceæ serve at all as a protection. At least, in the one species, the fertilisation of which I have very often witnessed, they do not. This species, Bunchosia gaudichaudiana, is regularly visited by several bees belonging to the genera Tetrapedia and Epicharis. These bees sit down on the flowers gnawing the glands on the outside of the calyx, and in doing so the under side of their body is dusted with pollen, by which, afterwards, other flowers are fertilised.4
There are here some species of Solanum (for instance S. palinacanthum) bearing on the same plant long-styled and short-styled flowers. The short-styled have papillæ on the stigma and apparently normal ovules in the ovary, but notwithstanding they are male in function, for they are exclusively visited by pollen-gathering bees (Melipona, Euglossa, Augochlora, Megacilissa, Eophila, n. g., and others), and these would probably never insert their proboscis between the stamens.5
In a few months I hope to be able to send you seeds of our white-flowered violet with subterranean cleistogamic flowers. I was surprised at finding that on the Sèrra (about 1,100 metres above the sea) this violet produced abundant normal fruits as well as subterranean ones, while at the foot of the Sèrra, though it had flowered profusely, I could not find a single normal fruit, and subterranean ones were extremely scarce.6
According to Delpino the changing colours of certain flowers would serve to show to the visiting insects the proper moment for effecting the fertilisation of these flowers.7 We have here a Lantana, the flowers of which last three days, being yellow on the first, orange on the second, purple on the third day. This plant is visited by various butterflies. As far as I have seen the purple flowers are never touched. Some species inserted their proboscis both into yellow and into orange flowers (Danais erippus, Pieris aripa), others, as far as I have hitherto observed, exclusively into the yellow flowers of the first day (Heliconius apseudes, Colœnis julia, Eurema leuce).8 This is, I think, a rather interesting case. If the flowers fell off at the end of the first day the inflorescence would be much less conspicuous; if they did not change their colour much time would be lost by the butterflies inserting their proboscis in already fertilised flowers.
In another Lantana the flowers have the colour of lilac, the entrance of the tube is yellow surrounded by a white circle; these yellow and white markings disappear on the second day.9
Mr. Leggett’s statements about Pontederia cordata appear to me rather strange, and I fear that there is some mistake. In all the five species of the family which I know the flowers are so shortlived, lasting only one day, that a change in the length of the style is not very probable.10 In the long-styled form of our highland Pontederia the style has its full length long before the flowers open. In my garden this Pontedaria is visited by some species of Augochlora collecting the pollen of the longest and mid-length stamens; they are too large to enter the tube of the corolla, and have too short a proboscis to reach the honey; they can only fertilise the long-styled and mid-styled forms, but not the short-styled.11
Among the secondary sexual characters of insects the meaning of which is not understood, you mention (“Descent of Man,” vol. i., p. 345) the different neuration in the wings of the two sexes of some butterflies. In all the cases which I know this difference in neuration is connected with, and probably caused by, the development in the males of spots of peculiarly-formed scales, pencils, or other contrivances which exhale odours, agreeable no doubt to their females. This is the case in the genera Mechanitis, Dircenna, in some species of Thecla, &c.,12
Mit wiederholtem herzlichsten Dank bin ich, werther Herr, in aufrichtiger Hochachtung treulichst der Ihrige | Fritz Müller.
Footnotes
Bibliography
Coleman, James R. and Coleman, Marina A. 1982. Reproductive biology of an andromonoecious Solanum (S. palinacanthum Dunal). Biotropica 14: 69–75.
Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.
Delpino, Federico. 1868–75. Ulteriori osservazioni sulla dicogamia nel regno vegetale. 2 parts. Milan: Giuseppe Bernardoni. [Originally published in Atti della Societa Italiana di Scienze Naturali Milano 11 (1868): 265–352; 12 (1869): 179–233; 13 (1870): 167–205; 17 (1874): 266–407.]
Delpino, Federico. 1873. Ulteriori osservazioni e considerazioni sulla dicogamia nel regno vegetale. Articolo IV. Delle piante zoidiofile. Atti della Società Italiana di Scienze Natural 16: 151–349.
Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.
Hazen, Tracy Elliot. 1917. The trimorphism and insect visitors of Pontederia. Memoirs of the Torrey Botanical Club, Proceedings of the semi-centennial anniversary of the Torrey Botanical Club 17: 459–84.
Leggett, William Henry. 1875. Pontederia cordata, L. Bulletin of the Torrey Botanical Club 6 (1875–9): 62–3.
Michener, Charles Duncan. 2007. The bees of the world. 2d edition. Baltimore: Johns Hopkins University Press.
West, David A. 2003. Fritz Müller. A naturalist in Brazil. Blacksburg, Va.: Pocahontas Press.
Translation
From Fritz Müller1 19 October 1877
Blumenau, Sa. Catharina, Brazil
19. October 1877.
Dear Sir!
Although I have hardly anything to tell you, I must not delay any longer in expressing my heartfelt thanks for your book on the different forms of flowers, which gave me great delight.2 It was very stimulating for me to follow all your remarkable observations and experiments on heterostyled plants in context and with so many valuable additions.
[. . .]
Repeating my hearty thanks, I am, dear Sir, with the deepest respect very faithfully yours | Fritz Müller.
Footnotes
Bibliography
Coleman, James R. and Coleman, Marina A. 1982. Reproductive biology of an andromonoecious Solanum (S. palinacanthum Dunal). Biotropica 14: 69–75.
Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.
Delpino, Federico. 1868–75. Ulteriori osservazioni sulla dicogamia nel regno vegetale. 2 parts. Milan: Giuseppe Bernardoni. [Originally published in Atti della Societa Italiana di Scienze Naturali Milano 11 (1868): 265–352; 12 (1869): 179–233; 13 (1870): 167–205; 17 (1874): 266–407.]
Delpino, Federico. 1873. Ulteriori osservazioni e considerazioni sulla dicogamia nel regno vegetale. Articolo IV. Delle piante zoidiofile. Atti della Società Italiana di Scienze Natural 16: 151–349.
Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.
Hazen, Tracy Elliot. 1917. The trimorphism and insect visitors of Pontederia. Memoirs of the Torrey Botanical Club, Proceedings of the semi-centennial anniversary of the Torrey Botanical Club 17: 459–84.
Leggett, William Henry. 1875. Pontederia cordata, L. Bulletin of the Torrey Botanical Club 6 (1875–9): 62–3.
Michener, Charles Duncan. 2007. The bees of the world. 2d edition. Baltimore: Johns Hopkins University Press.
West, David A. 2003. Fritz Müller. A naturalist in Brazil. Blacksburg, Va.: Pocahontas Press.
Summary
Doubts that glands of calyx of cleistogamic Malpighiaceae serve as protection.
Some species of Solanum bear long- and short-styled flowers on same plant.
Changing colours of some flowers may show insects the proper moment for fertilisation.
Doubts that the style of Pontederia cordata changes length.
Sexual difference in wings of some butterflies due to development in male of scales that emit odours to excite female.
Letter details
- Letter no.
- DCP-LETT-11191
- From
- Johann Friedrich Theodor (Fritz) Müller
- To
- Charles Robert Darwin
- Sent from
- Santa Catharina, Brazil
- Source of text
- Möller ed. 1915–21, 2: 363–4; Nature, 29 November 1877, pp. 78–9
Please cite as
Darwin Correspondence Project, “Letter no. 11191,” accessed on 29 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-11191.xml