Primula siberica seems to be the only non-dimorphic species. Has made over one hundred Primula crosses.
Regrets Henslow's illness.
Down Bromley Kent
My dear Sir
Very many thanks for the Primulas (& about common Primrose) which I received this morning & examined. Only one was dimorphic: but I have every reason to suppose the others would have been so, had you possessed a greater number of plants.— P. Siberica, however, seems to differ from all other species in not being dimorphic.—
I have been deeply grieved to hear about Prof.— Henslow—
Yours very sincerely | C. Darwin
As P. Siberica is apparently so exceptional, would you ask M
But if your plants have been increased all by offsets from same original plant, it will be no use to send them. As the character is permanent by offsets.
I do not know whether I shall succeed in making out the meaning of the dimorphism; but I have not been idle, for I have made much above 100 crosses with the pollen of the different sizes.
The lot sent has been most interesting to me.— Pray thank M
Do not trouble yourself to write if you can at any time send me other specimens of P. Siberica—
- f1 3110.f1Dated by the relationship to the letters to Daniel Oliver, 23 March  and 1 April  and by the reference to John Stevens Henslow's illness.
- f2 3110.f2CD had asked Oliver to send him specimens of various species of Primula (see letter to Daniel Oliver, 23 March ).
- f3 3110.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), CD mentioned that `unless indeed this single specimen was anomalous', P. sibirica was not dimorphic (ibid., p. 81; Collected papers 2: 48--9).
- f4 3110.f4Charles William Crocker was foreman of the propagating department at the Royal Botanic Gardens, Kew.