From John Denny 16 August 1879
Stoke Newington,
August 16.th. 1879
Dear Sir
You may perhaps remember, we corresponded seven years ago, with reference to some varieties of the Pelargonium, which while similar to all appearance, (save being some what more robust) to the other varieties in my house, “proved to be sterile, excepting with each other.”1
I’ve since found that th⟨e⟩ two varieties are fertile with some varieties raised by Mons. Lemoine, but which varieties evidently arose either from self-fertilization, or crosses between these two, viz, Beautie de Surressnes & the Duke of Cornwall, or sports as was the case with the Doubles which were sports off Beautie de Surressnes, & all the varieties thus raised by Lemoine proved to be sterile—with the other varieties of the Zonal Pelargonium. I therefore consider them to constitute “a distinct Class”—or Species—as some would call them2
As you took much interest in my communication upon this subject at the time I refer to and—In reply to my Communication (Letter of July 15 1872) you remarked, that you considered I had made an important discovery as bearing upon the Origin of Species. As you could only account for the facts related by supposing that a variety—through cross breeding or some other cause—had arrived at a condition, which resulted in “a stop”, & refusal to be fertile with other varieties of its kind.3
You also asked me if I met with any thing in my cross breeding experience that further bore upon this point—or seemed of scientific interest—to communicate it to you
I must first tell you that I’ve continued to raise several thousand seedling Pelargoniums yearly, and as you may have seen by the horticultural press, have immensely improved the form & size of the flower but nothing has occurred of a scientific nature that I deemed worthy of troubling you with until now recently.4
You must bear in mind that the origin of the varieties Beautie de Surressnes & Duke of Cornwall were unknown to me. These being the varieties I quoted as infertile with the other varieties of Zonal pelargoniums—& these two varieties might have been raised from seed, or they might have resulted as sports.— I failed in any way to trace their origin
I now purpose describing a variety, & its origin which may tend to throw some light upon the probable origin of these varieties & possibly upon the origin of what are called species.
As I consider the matter of importance & interesting, I will go into details & endeavour to make myself intelligible
Upon a White Variety of my own raising, I one day observed at the top of one of its branches a very considerably larger flower than its fellow⟨s⟩ also that the leaves of this twig were larger & stouter.
I consequently made a cutting of & propagated this twig which grew into a plant of a much more robust habit than the the plant from which it was taken, & which also maintained its improvement in size & substance of blossom.— the cuttings taken from this plant have also increased in robustness of growth, until they resemble in form of foliage & habit precisely that of Beautie de Surressnes & the Duke of Cornwall. The flower also resembles in form & substance that of those varieties, save in colour—they being respectively pink, & scarlet.
But now I come to what seems to me the most important point—(viz) that this sport seems to be like the class refered to, equally sterile with other varieties—for I can neither get it to seed from the application of the pollen off the plant from which it was taken—or any other variety that I have as yet tried upon it, nor will its pollen fertilize.5
I do not now possess a plant of Beautie de Surressnes.—but I intend to obtain one, on purpose to try if they will prove fertile upon one another.
I have had no experience in sports of other plants—, but it would be interesting to know—if when they show considerable variation from the pla⟨nt⟩ from which they were tak⟨en⟩ whether they prove sterile with the pollen of its mother plant & similar varieties. Because should such be the case—it would undoubtedly indicate the origin of Species.
I shall continue my endeavours to cross this sport with my other varieties—. & I will try it with the pollen of Beautie de Surressnes,—also its pollen upon that variety, & should be happy to report to you with what result—if you consider the matter of interest to you
Dear Sir | Yours faithfully | John Denny
Chas. Darwin Esqre
Footnotes
Bibliography
Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.
Dauthenay, Henri. 1897. Les Geraniums: (Pelargonium zonale et inquinans); description et culture. Paris: Octave Doin.
Denny, John. 1872a. The relative influence of parentage in flowering plants. Gardeners’ Chronicle, 29 June 1872, p. 872, 6 July 1872, pp. 904–5.
Denny, John. 1872b. On cross-breeding pelargoniums. Florist and Pomologist (January 1872): 10–12, (February 1872): 34–6, (March 1872): 50–3.
Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.
Summary
JD communicates, after seven years, news of a new "sport" of Pelargonium, sterile both with other varieties and with the mother plant, thus indicating that it is possibly a new species.
Letter details
- Letter no.
- DCP-LETT-12195
- From
- John Denny
- To
- Charles Robert Darwin
- Sent from
- Stoke Newington
- Source of text
- DAR 162: 161
- Physical description
- ALS 10pp damaged
Please cite as
Darwin Correspondence Project, “Letter no. 12195,” accessed on 28 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-12195.xml