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Darwin Correspondence Project

To George Bentham   30 November [1861]1

Down. | Bromley. | Kent. S.E.

Nov. 30th

My dear Bentham

Your letter of the 26th is very valuable to me. Oxalis & ægiphilos seem capital cases. I will follow your suggestion about violets & today had several plants put into my experimental garden: I have attended & experimented on the regular flowers of Viola: they require insect-aid for at all perfect fertility; & as insects do not freely visit them, I have always supposed that the imperfect flowers produced seeds by parthenogenesis to keep the stock up; but I will attend to this subject next summer.—2

Thymus is a different case from Primula: some individuals being hermaphrodite & some female by abortion of anthers. In the English Thyme this abortion to a certain limited extent depends on growing in dry stations (I counted hundreds of plants).3 The garden Thyme seems to produce both forms irrespective of conditions. The female plants of the garden thyme produce nearly double the weight of seed, compared with the Hermaphrodites: the wild English female Thyme produces more than double the weight.— There is a slight difference in the stigmatic tissue in the Hermaphrodite & Female plants.— As you seem interested in dimorphic plants, I thought that perhaps you would like to hear these details.—

Since the above was written I have received your list of Oxalis, for which very many thanks.—4

Pray believe me— Yours sincerely & obliged | Ch. Darwin


Dated by the relationship to the letter from George Bentham, 26 November 1861.
There are some lengthy notes describing CD’s examination of the flower parts of Viola canina, dated May 1862, in DAR 111: 3–6.
CD had studied the morphology of thyme plants during the summer of 1861 (see letter to Asa Gray, 21 July [1861]). There are notes discussing his observations in his Experimental book (DAR 157a).


Thanks GB for valuable letter [3331].

Will follow his suggestion about violets.

Discusses differences between Thymus and Primula.

Letter details

Letter no.
Charles Robert Darwin
George Bentham
Sent from
Source of text
Royal Botanic Gardens, Kew (Bentham Correspondence, Vol. 3, Daintree–Dyer, 1830–1884, GEB/1/3: f. 691)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 3335,” accessed on 4 March 2021,

Also published in The Correspondence of Charles Darwin, vol. 9