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Darwin Correspondence Project

From Daniel Oliver   23 April 1862


Wednesday | 23. Apr. 1862

Dear Sir

Here are the flowers of Oxalis as requested. I do not perceive anything distinctly dimorphic.—1

My examining of the plant had reference chiefly to the aestival small flowers: they are very remarkable.— I altered a little the “definition” of the two groups of dimorphism in the paper which you so kindly looked over (& tho’t worth printing!).—2 Making one group with the Dimorphism manifest in, primarily, a separation more or less of the sexual organs, accompanied or not by alteration in the outer whorls.— (Thus including all wholly or partially diclinous plants,—Catasetum, Primula, &c) & the other group marked primarily by alteration primarily in envelopes of the flower without separation of the sexes.

Of course this is only the morphologl. definition

After discussing their function &c. we may class them in corresponding group by other characters.

Very sincerely yours | Danl. Oliver


See letter to Daniel Oliver, 20 [April 1862] and n. 2. There are observational notes relating to these specimens, dated 24 April 1862, in DAR 109 (ser. 2): 5. CD subsequently concluded that Oxalis acetosella was not dimorphic (see Forms of flowers, pp. 181–3).


Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.


Distinguishes two kinds of floral dimorphism: that affecting sexual organs and that affecting outer envelopes.

Letter details

Letter no.
Daniel Oliver
Charles Robert Darwin
Sent from
Source of text
DAR 173.1: 14
Physical description
ALS 3pp

Please cite as

Darwin Correspondence Project, “Letter no. 3515,” accessed on 20 May 2022,

Also published in The Correspondence of Charles Darwin, vol. 10