Down, Beckenham.
July 1. 1876
My dear Sir,
I am much obliged to you for having sent me your two reports on the culture of the Poppy, & I have read them with much interest.1 Your observations seem very important and promising under a practical point of view; and I am glad to observe that you keep up that zeal which you have always showed. I have sown the seeds, from mere curiosity to see the plants; but from the spring being so cold I fear they will not do much good.2
I am now going to suggest a subject which if I had been a younger man I should certainly have investigated. No doubt you know that M. Jourdan splits up some of the species of Draba, Papaver, &c, each into more than a score of subspecies, and he asserts that they may be sown close together & never intercross, so that each keeps true to its kind by seed.3 Now if I understand rightly, the numerous vars of P. somniferum, which grow mingled in your fields, come true by seed with the exception of certain monstrous forms. How is this, and why do they not intercross, like the vars of cabbages carnations, &c in our gardens? I would suggest your castrating the unexpanded flowers of two or three vars, and by leaving them discover whether pollen is brought to them by insects. (What insects visit the flowers?). If they seed even to a moderate extent, I would then try the effects of mixing pollen of the same variety, but taken from a distinct plant (pray attend to this latter point,)4 with pollen from another variety, and then place the mixed pollen on the stigmas of the first variety without castrating the flowers. Sow the seeds and observe whether the seedlings are hybridised. If they are hybridised & yet you are able to raise pure vars from seed collected where many vars grow mingled together, then we should have evidence that forms which most botanists would certainly rank as mere varieties, are so far constituted like species, that they do not naturally intercross notwithstanding that pollen is carried from plant to plant by insects.
Wishing you all success in your valuable researches, & that you may keep your health, I remain | my dear Sir | Yours very faithfully | Charles Darwin
Please cite as “DCP-LETT-10555,” in Ɛpsilon: The Charles Darwin Collection accessed on