From John Denny 20 July 1872
Stoke Newington
July 20th. 1872
Dear Sir
In the first place allow me to thank you very much for the compliment you pay me, in suggesting that the results of my experiments in the fertilization of the Pelargonium family should be communicated to a scientific society. & more especially for your kind offer to be the medium of its communication; believe me I thoroughly appreciate both the compliment & your kindness.1
But you must permit me to observe, that it is one thing to write a paper for a Horticultural Congress, and another to do so for the Linnean Society, & moreover one worthy of your introduction.2
An undertaking I hardly feel myself qualified to attempt, at any rate before doing so it would be necessary to decide (if possible) the essential point of my case, viz, the origin of the Duke of Cornwall, & other var. in question.
From my statements it seems you assume them to be varieties only of the zonals I’ve tried to cross with them.3 if you refer to my paper, & to the Florist, you will see I speak of them as being “to all appearance but mere varieties of the zonal section”.4
Hence the difficulty I speak of in the early part of my paper.. that for the want of some distinctive evidence, or line of demarcation, we are unable to decide what are varieties, & what belong to distinct species.
There is I presume no means of ascertaining this—as regards the plants in question?
The Duke of Cornwall is a robust grower, but in all other respects, resembles both in flower & foliage—the ordinary varieties of the Scarlet section; it is a very old variety, and at present I am quite unable to trace its parentage.5
Beauté de Suresnes, & Dr. Muret are similar in habit of growth; & of french origin, so I fear their history is not easily obtained either.
These varieties may possibly have sprung from one, & a distinct parentage from the zonals I’ve tried to cross with them.6
For instance, in another section of the Pelargonium family.—the class known by the name of “Fancies” seem to be quite distinct from the class called “Show” or large flowering, for they will not cross, yet to all appearance they are sufficiently alike, to lead one to suppose them to be but varieties.7
Therefore it seems to me, that unless I could prove that these varieties I name, have descended from the same parents as those I’ve attempted to cross with them, my case is worthless.8
In answer to your remark, I would observe I have tried hundreds of times, & numerous varieties of the zonal section, to effect a cross upon, & from these Vars. failing to produce fructification in every instance, unless by using their pollen upon themselves or upon each other of these varieties. & upon, or from the double varieties which sprang from Beauté de Suresnes.
With regard to the Ivy leaved variety—Peltatum Elegans, the case is clearer, for I suppose this section of the Pelargonium family—represents a distinct species “or a supposed distinct species.” but with these I should like to continue my experiments at least another season, & to let the results become more fully developed, & more numerous, before reporting upon them to a scientific Society.
I am this season putting the pollen of Peltatum Elegans upon the zonal section—& I seem to have some seed approaching maturity from this cross; if so this variety of the Ivy-leaved section is reciprocally fertile with the zonal.
With regard to your remark respecting the exclusion of insects,—by the aid of a powerful glass,—there seems to me no difficulty in ascertaining that the stigma (in the pelargonium family) is in a state of perfect virginity, viz, that there is not a grain of pollen on it; & I assume that as soon as I have covered it completely with the desired pollen, that it is proof against the receipt of any other; or at any rate that the chances are as a thousand to one, against its becoming impregnated subsequently.9
The remarks I make in my paper—(you see) rather anticipate the probability of the influence resulting from constitution &c. &c. being different, when distinct species are employed, from my experiments on varieties, so that Gärtners conclusions may be correct without upsetting mine.10
But to be able to form any decided opinion upon the various points mooted at the commencement of my paper, we require an accumulation of reliable evidence.—& facts more distinctly given than I’ve yet seen.
I am now trying some experiments in crossing Lilies of more opposite characters, to see the effects of parentage in that family, as regards transmission of size, shape, color, & perfume.
Professor Dyer tells me he has Gärtners works in hand, but it did not appear to be clear, how soon they would be ready for publication.11
We took some steps at our meeting on Wednesday of the Roy. Horticultural Society regarding Ayrton’s scandalous conduct towards Dr. Hooker. Not at all too soon for as I took the liberty to remark, it was a disgrace to the Society not to have been the first to move in the matter12
Fearing my prodigiously long letter has long since tired you out | Believe me | Dear Sir | to remain yours faithfully | John Denny
CD annotations
Footnotes
Bibliography
Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.
Gärtner, Karl Friedrich von. 1849. Versuche und Beobachtungen über die Bastarderzeugung im Pflanzenreich. Mit Hinweisung auf die ähnlichen Erscheinungen im Thierreiche, ganz umgearbeitete und sehr vermehrte Ausgabe der von der Königlich holländischen Akademie der Wissenschaften. Stuttgart: E. Schweizerbart.
Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.
Wilkinson, Anne. 2007. The passion for pelargoniums: how they found their place in the garden. Stroud: Sutton Publishing.
Summary
Thanks CD for his offer to communicate the results of his experiments with Pelargonium to the Linnean Society. Prefers to continue experimenting for at least another season before doing so.
Letter details
- Letter no.
- DCP-LETT-8421
- From
- John Denny
- To
- Charles Robert Darwin
- Sent from
- Stoke Newington
- Source of text
- DAR 162: 160
- Physical description
- ALS 16pp †
Please cite as
Darwin Correspondence Project, “Letter no. 8421,” accessed on 29 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-8421.xml
Also published in The Correspondence of Charles Darwin, vol. 20