Comments on notes made by THF on Passiflora and Tacsonia. Suggests he examine more species. Recalls his own observations on P. princeps and Tacsonia.
Down. | Beckenham | Kent. S.E.
My dear Farrer
Your notes strike me as good & I agree with Hooker that they are quite worth publication; but I wish you could first have examined more species.— Especially Passiflora princeps, a splendid species, (as I believe called) in which, as I remember (for I cannot find my notes wh. I suppose I made) there were some (3?) regular rounded passages or holes through the corona to the nectary. The nectary, if my memory serves me, was constructed like that of Tacsonia.
My Tac: van volxenis has produced, without any aid in fertilisation, plenty of fruit with an abundance of apparently good seed: the fert: is effected by each of the three stigmas slowly curving upwards (flowers being pendent) & in thus moving they generally touch one of the anthers of same flower.—
See Hildebrand in pamphlet last sent, on abortion of stamens in uppermost or final dichogamous flower in Geranium: this seems an eminently interesting case of abortion— attend to other such cases— see how is the last flower in reference to its capacity for being fertilised.—
Yours very sincerely | C. Darwin—
You ought to set up in cool Hothouse & Greenhouse.— Could you not go to Kew & see if any Passifloras are now in flower?
- f1 6945.f1The year is established by the relationship between this letter and the letter from T. H. Farrer, 17 October 1869.
- f2 6945.f2For Farrer's notes on Passiflora and Tacsonia, see Correspondence vol. 17, Appendix IV. Farrer discussed Passiflora princeps, but noted that he had not seen many specimens. Farrer received specimens of some passifloras, but not P. princeps, from Joseph Dalton Hooker (letter from J. D. Hooker to T. H. Farrer, 23 October 1869, Linnean Society Archives). Farrer evidently added more information on this species after visiting the Royal Botanic Garden, Kew, in November 1869 (the additions are not transcribed in the appendix, but are in the Linnean Society of London, MSS Case 6B, MS. 510).
- f3 6945.f3The reference to the structure of the nectary in Passiflora princeps and Tacsonia has not been found in CD's notes.
- f4 6945.f4Tacsonia van volxemis is now Passiflora antioquiensis.
- f5 6945.f5CD had evidently sent Farrer his copy of Friedrich Hildebrand's paper `Weitere Beobachtungen über die Bestäubungsverhältnisse an Blüthen' (Further observations on the conditions of pollination in flowers; Hildebrand 1869). Hildebrand noted that in the protandrous Geranium macrorrhizum the earliest flowers had stamens aborted and concluded that this was because there was no use for fertile stamens when no developed stigmas were available (Hildebrand 1869, p. 480). CD scored this section in his offprint of the article, which is in the Darwin Pamphlet Collection--CUL.
- f6 6945.f6See above, n. 2.