skip to content

Darwin Correspondence Project

To Daniel Oliver   [12 April 1863]1

Down Bromley Kent


Dear Oliver

It is a shame to trouble, but will you tell me whether ovule of Primula is “anatropal” nearly as figured by Gray p. 123 Lessons of Botany.—or rather more tending to “amphitropal”.—2 I never looked at such a point before. Why I am curious to know is because I put pollen into ovarium of monstrous Primroses, & now after 16 days, & not before, (the length of time agrees with slowness of natural impregnation) I find abundance of pollen-tubes emitted, which cling firmly to ovules & I think I may confidently state penetrate the ovule; but here is odd thing   they never once enter at (what I suppose to be) the “orifice” but generally at c the chalaza, when they fall.—3

Do you know how pollen-tubes go naturally in Primula? do they run down walls of ovarium & then turn up the placenta & so debouch near the “orifices” of ovules?

If you thought it worth while to examine ovules, I would see if there are more monstrous flowers & put pollen into ovarium & send you the flowers in 14 or 15 days afterwards. But it is rather troublesome, I would not do it unless you cared to examine the ovules. Like a foolish & idle man I have wasted a whole morning over them.—

When does Hooker return?4

Yours most sincerely | C. Darwin

One line in answer would suffice—

In 2 ovules there was an odd appearance as if the outer coat of ovule at the chalaza end (if I understand the ovule) had naturally opened, or withered, where most of the pollen tubes seemed to penetrate which made me at first think this was a widely open foramen.5 I wonder whether the ovules would could be thus fertilised!


The date is established by the relationship between this letter and the letter from Daniel Oliver, 14 April 1863, and by the observations on ‘monstrous Primroses’ (see n. 3, below); in 1863, 12 April was a Sunday.
CD wondered whether Primula ovules were parallel to and fused with the stalk of the ovule (‘anatropal’), or whether the ovule was positioned at a right angle to the stalk (‘amphitropal’) (see A. Gray 1857, p. 123, for diagrams). CD’s lightly annotated copy of A. Gray 1857 is in the Darwin Library– CUL (see Marginalia 1: 347).
CD’s experimental notes (DAR 108: 165 v.) record that he began this experiment on 26 March 1863 and first observed pollen grains emitted on 11 April. Pollen-tubes in flowering plants normally enter the ovule through the micropyle or orifice. According to Francis Darwin (ML 2: 333), the observation that pollen-tubes might enter through the chalaza was first published by the Dutch botanist Melchior Treub (Treub 1891).
Joseph Dalton Hooker was on a trip to the channel islands of Jersey and Guernsey (see letter from J. D. Hooker, 20 April 1863); Oliver was assistant to Hooker in the herbarium at the Royal Botanic Gardens, Kew (R. Desmond 1994).


Working on monstrous Primula. Is ovule anatropous as Asa Gray says, or amphitropous? Does he know natural path of pollen tubes in Primula. Can the tube enter the ovule by the chalaza?

Letter details

Letter no.
Charles Robert Darwin
Daniel Oliver
Sent from
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4083,” accessed on 23 March 2019,

Also published in The Correspondence of Charles Darwin, vol. 11