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Letter 7254

Farrer, T. H. to Darwin, C. R.

29 June 1870


Has procured a Passiflora flower at last. Structure suited for humming-birds rather than bees.


Bd of Trade

29 June/70

My dear Mr Darwin

I have at last got a flower of Passiflora Princeps.f1 You werequite right, as you seem always to be   The lower or inner coronas,or whatever they are, which cover the nectary, neither fit closeto the style, nor lap over one another so as to prevent the entranceof a stiff object. There are wide gaps by which a pin does get tothe bottom and comes out covered with nectar. But the style isvery long: the flower sub-erect: and, so far as I can see, the anthersand stigmas do not droop down as in P. Caerulea. The consequence isthat the distance between these organs and the nectary & their relativeposition is such that a bee on the top of the outer coronas would nottouch them. Add to this that the two outer coronas are very littledeveloped: and that the third closes round the style so as to makeit an inch from the entrance to the bottom of the nectary— I thinkwith all this we have a correlation of parts suited for Humming birds& not for Bees.—though not exactly the correlation I noted in theothers.f2

I will certainly come and see you as you so kindly suggest—butam very busy till the Session is over—which I find the best thing.It is the leisure & the tired hours which are difficult to bear.f3

Sincerely yours | T H Farrer

We have been deeply interested in watching the wonderful motionsof Passifloras in climbing. They seek & find & hold on & pull up likean animal

DAR 164: 65



CD had advised Farrer to look at the pollination mechanism ofPassiflora princeps in October 1869; Farrer had obtained an imperfectspecimen in November 1869 (see Correspondence vol. 17, letter toT. H. Farrer, 20 October [1869], and letter from T. H. Farrer, 5 November 1869). Passiflora princeps is now P. racemosa, the redpassionflower.
Farrer had been engaged in a discussion with CD and Fritz Müllerabout Passiflora and Tacsonia;see letter to T. H. Farrer, 13 [May 1870] and n. 3. See alsoCorrespondence vol. 17, Appendix IV.
Farrer’s wife, Frances, had died in May 1870 (see letter fromT. H. Farrer, 17 May 1870). Farrer was permanent secretary of theBoard of Trade.
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