Has put Drosera off while amusing himself with Primula and orchids.
Dionaea is prettily adapted to weight detection.
Down. | Bromley. | Kent. S.E.
My dear Sir
I was pleased to see your handwriting again, & sincerely hope that you are
quite recovered from your long illness. Take warning from me & do not work too
hard.— Very many thanks for information about P. ciliata &
var.— I was sure it could not be an
ordinary variety; it differed too much & I was utterly perplexed what
to do about it.— I sh
I hate changing work & I have so many irons in the fire that I have stopped looking after Dionæa.— I return your nice sketches which make me quite envious. I do not of course mean to attempt any minute work at structure; merely a few functional observations relatively to Drosera (which alas I have resolved to put off for another year, for I have amused myself too long over Primulas & Orchids).—
I have made out very little on Dionæa: merely that the leaf behaves very
differently when a fly, or only bit of cork & nothing is
caught.— When a fly is caught much acid mucous is poured out as in Drosera.
And the leaf must absorb so as to perceive when it has caught a fly— The
``tortoises'' seem to be the secretors & absorbers &
appear to me to be strictly homologous with the glands in
Drosera.— It is odd that meat, flies, sol. of C. of
ammonia, will not excite movement or secretion; the sensitive filament must
be touched to set all in action. The sensitiveness of the filament is
prettily adapted: drop of water falling on them, or strong wind through pipe produces no
effect; but a touch by a woman's Hair held with one inch length free will
suffice. There is a pretty difference with Drosera: the latter does not care for a
single rough touch with even a needle, but a weight left on the gland of
But I must not run on. | Pray believe me | Yours very sincerely | Charles Darwin
- f1 3251.f1Dated by the relationship to the letter to J. D. Hooker, 6 September .
- f2 3251.f2Oliver's letter has not been found. CD had asked Joseph Dalton Hooker to pass on to Oliver his query about Primula ciliata and P. ciliata var. purpurata (see letter to J. D. Hooker, 6 September ).
- f3 3251.f3In his paper `On the two forms, or dimorphic condition, in the species of Primula, and on their remarkable sexual relations', Journal of the Proceedings of the Linnean Society (Botany) 6 (1862): 77--96 (Collected papers 2: 45--63), CD acknowledged having received specimens of Primula ciliata and P. ciliata var. purpurata from Oliver. Of the latter, CD stated that the case was `hardly worth giving, as the variety purpurata is said to be a hybrid between this species and P. auricula' (Collected papers 2: 48).
- f4 3251.f4P. farinosa, the bird's-eye primrose is common in damp woods in northern England and southern Scotland. It is not described in CD's paper on the dimorphic condition of Primula. By the time CD published a fuller account of this study in 1877, however, he had been able to examine specimens of this species. See Forms of flowers, pp. 45, 224, and 273.
- f5 3251.f5Oliver had greatly assisted CD's study of the sensitivity of the leaves of Dionaea and other insectivorous plants to various substances (see Correspondence vol. 8). CD continued to investigate this topic for a number of years, not publishing his results until 1875 (see Insectivorous plants). CD's notes on Primula are in DAR 108 and 111, and those on orchids are in DAR 70.