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Darwin Correspondence Project

From Thomas Meehan   22 September 1874

Sep 22 1874

Chas. Darwin Esqr

My Dear Sir

You wrote to me last year acknowledging the photo—of my friend Prof. Cope, and stating that my own sent to you through Mr. Rosengarten had failed to come to hand.1 I had no more at that time, and only now have had a chance to have a few more taken.

Knowing it would interest you, I mailed a few weeks ago a copy of my address at Hartford, and also a brief newspaper report of the discussions thereon.2 I think, as you will see I believe, that my good friend Prof. Gray did not apprehend the full nature of my facts, as I saw him enter the hall, when the paper had been half read through.3 I think his remarks have however tended to misdirect the public press. The Popular Science Monthly, for instance, remarks, “on the contrary, all except the Author regarded the facts as favoring Mr. Darwins Theory of Natural Selection”.4 I am sure there was nothing in my paper, nor in any subsequent remarks of mine, which warranted the “exception”. My point was that there are other factors in the origination of form, besides—not opposed to—Natural Selection, both acting perhaps in conjunction therewith.

I am still gathering facts in relation to the connection between color and sex in plants;5 but my numerous occupations prevent me from working them up as rapidly as I would like. One of the prettiest facts is in Daucus Carota. In this part of the world the umbel often has male flowers sparingly. Usually one in the center. That is the gynoecium is arrested at an early stage of its growth, and the stamens become remarkably perfectly formed. These male flowers are always highly colored.6 Still in these, as in most other studies of natural phenomena, come in contradictions which make me hesitate about any positive conclusion. Thus the pistils of Corylus Americana and I suppose others, are deeply rose tinted,—while the male catkins (all catkins?) are in a sense colorless.7

I am continually impressed with the apparent fact that the world knows comparatively nothing of plants as living beings. Most is dry Herbarium knowledge. And we are far behind you in Europe. Still we have a few ardent workers, among whom the best is possibly Dr. Engelmann, and I wish he would publish more. I have just a brief note from him in Colorado, where he is rusticating this Autumn, in which he tells me he has discovered remarkable behaviour in the stamens and pistils of the Gentians of that Section—the large flowered ones acting differently to the small (including Swertias) and which has a great and interesting bearing on cross and Insect fertilization.—8 Forgive this gossip. “Pen in hand” is a great temptation.

Very truly your | Thomas Meehan


See Corrrespondence vol. 21, letter to Thomas Meehan, 19 March [1873]. Meehan refers to Edward Drinker Cope and Joseph George Rosengarten.
Meehan refers to his address ‘Change by gradual modification not the universal law’ delivered to the American Association for the Advancement of Science at Hartford, Conn., on 13 August 1874 (Meehan 1874). CD’s annotated copies of a newspaper reprint of the address and a newspaper extract reporting on the general discussion following the address are in DAR 45: 183–4. The newspapers from which the extracts were taken have not been identified. The discussion was not published in the Proceedings of the American Association for the Advancement of Science.
In the discussion following Meehan’s address, Asa Gray had argued that Meehan’s examples could be accounted for as monstrosities and the fact that the same characteristics could be produced from seed over successive generations proved nothing since some monstrosities, such as additional fingers or toes in humans, were heritable.
The anonymous note ‘New species by sudden variations’ appeared in Popular Science Monthly, October 1874, pp. 764–5. The passage referred to by Meehan reads: ‘even Mr. Meehan himself, regarded the argument as a contribution to the theory of evolution, while all but the author were of the opinion that it was quite consistent with the principle of natural selection, and, indeed, had already been taken into the account by Mr. Darwin.’
Meehan associated bright colour and variegation with what he termed the ‘male principle’. He discussed his theory and observations on this point in his letter of 3 March 1873 (Correspondence vol. 21). For more on his views about colour in relation to sex, see Meehan 1869 and 1870.
Daucus carota (wild carrot) has inflorescences composed of a primary umbel and secondary, tertiary, and sometimes quaternary umbels, each with several individual flowers, both hermaphrodite and male. The primary umbel has mostly hermaphrodite flowers with male flowers usually found near the centre of the umbel; the other umbels have mostly male flowers. Most flowers are white, but the central flower of the primary umbel is often a deep red or purple and is hermaphrodite. The flowers are protandrous, that is, the male parts mature before the female (Lamborn and Ollerton 2000, p. 446). In Forms of flowers, p. 8, CD noted that he obtained a seed from artificially fertilising the central purple flower.
Corylus americana (the American hazelnut) has separate male and female flowers with both types present on the same tree.
George Engelmann had described several species of gentian of the Rocky Mountain region (G. Engelmann 1863). Swertia (felwort) is a genus in the family Gentianaceae. Many species formerly identified within this genus are now placed in the related genus Frasera (elkweed). Meehan probably refers to the section Crossopetalum or Gentianella of the genus Gentiana (now the genus Gentianopsis); Engelmann had described a new species, G. barbellata (the perennial fringed gentian), in G. Engelmann 1863, p. 216. Engelmann later noted, having observed living plants, that the versatile anthers changed position as the flower developed; they were pointing inwards, became horizontal and shed pollen when the flower opened, then turned over backwards on the filament with the empty cells directed outward (G. Engelmann 1878, p. 193 n.).


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

Engelmann, George. 1863. New species of Gentiana, from the alpine regions of the Rocky Mountains. Transactions of the Academy of Science of St. Louis 2 (1861–8): 214–18.

Engelmann, George. 1878. Gentianeæ. In Report upon United States geographical surveys west of the one hundredth meridian. Vol. 6, Botany. Washington: Government Printing Office.

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

Meehan, Thomas. 1869. On the sexes of plants. Proceedings of the American Association for the Advancement of Science (1869): 256–60.

Meehan, Thomas. 1874. Change by gradual modification not the universal law. Proceedings of the American Association for the Advancement of Science (1873) pt B: 7–12.


Sends CD his photo

and a copy of his address at Hartford ["Change by gradual modification not the universal law", Proc. Am. Assoc. Adv. Sci. (1874) pt 2: 7–12]. Does not believe his observations are unfavourable to natural selection but feels there are other factors involved in the origin of form.

Discusses further his work on colour and sex in plants; the linking of high colour and maleness.

Letter details

Letter no.
Thomas Meehan
Charles Robert Darwin
Sent from
Gardeners’ Monthly , Germantown, Pa.
Source of text
DAR 171: 110
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 9651,” accessed on 22 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 22