Variations in the structure of Pelargonium flowers.
Do you remember calling my attention to certain flowers in the truss of Pelargonium not being true, or not having the dark shade on the 2 upper petals? I believe it was Lady Lubbock's observation.—
I find, as I expected, it is always the central or sub-central flower; but what is far more curious, the nectary, which is blended with the peduncle of the flowers, gradually lessens & quite disappears; as the dark shade on the 2 upper petals disappears.— Compare the stalks, in the two enclosed parcels, in each of which there is a perfect flower.—
Now if your Gardener will not be outrageous, do look over your Geraniums & send me a few trusses, if you can find any, having the flowers without the marks, sending me some perfect flowers on same truss.—
The case seems to me rather a pretty one of correlation of growth; for the calyx also, becomes slightly modified in the flowers without marks.—
Ever yours very truly | C. Darwin
I sent old Swammerdam this morning.
- f1 2390.f1Although the letter is endorsed ‘1859’, it seems more likely that it was written in the late summer of 1858. The abnormality discussed in the letter was cited in Origin, p. 145, in a chapter that CD completed by 22 October 1858 (‘Journal’; Appendix II). From CD's reference, it is clear that the pelargoniums were in flower, making August to September a probable date. See also n. 4, below.
- f2 2390.f2Harriet Lubbock was John Lubbock's mother.
- f3 2390.f3The case is cited in Origin, p. 145, as evidence for the correlation of variations in plants. It was further discussed by CD in 1861 in ‘Cause of the variation of flowers’ (Collected papers 2: 43–5).
- f4 2390.f4Swammerdam 1758, an English translation of Jan Swammerdam's Bybel der Natuure (Leiden, 1737). CD's copy of the work is in the Cambridge University Library. It had been given to Erasmus Darwin by Josiah Wedgwood I and passed on to CD by his father Robert Waring Darwin in 1827. A further inscription indicates that CD gave the volume to William Erasmus Darwin in 1858. Lubbock referred to Swammerdam's description of the dipteran Stratiomys in his paper on the ova and pseudova of insects (Lubbock 1859). The paper was received by the Royal Society on 10 November 1858 and read at the meeting of 9 December (see letter to John Lubbock, [November 1858]).