From George Henslow   20 October 1876

Dear Sir,

I see advertised in “Nature” a new work by yourself on “The effects of Cross and Self-fertilisation of Plants: and you will see a notice of mine on the latter subject.¹ I should esteem it a great kindness if you would tell me if the “conclusions” there given coincide with your own: and, if not, I should be glad to hear where you think I may be wrong in any way.

There are some points I ⁠⟨⁠    ⁠⟩⁠ ⁠⟨⁠    ⁠⟩⁠ present, of sufficient observation  For example: the cause of protogyny. I find that Statice and Plantago² both develop their whorls in the same, but not the usual order, as follows:—Calyx, Corolla, stamens, pistil   The pistil, however, rapidly outgrows the stamens and the styles elongating protrude beyond the corolla & mature first.

This seems to indicate the fact that the early development of the corolla tends to arrest that of the stamens (which in most flowers precede it) and so enables(?) the pistil to mature first.³ But why this is so I cannot yet see. If you can throw any light on this, I should be much obliged for your help.

Luzula campestris is another good example of protogyny.⁴

I have just noted some more instances corroborative of my statement that self-fertilisation is a relative condition. Thus some flowers of Œnothera biennis with petals $\frac{1}{2}$ inch long were self-fert^g. and in that stage—exactly resembled the normal flowers of Œ. parviflora! Which is also self-fertilising.⁵

Does not this fact throw out a hint as to the origin of some “species”?

Similarly Epilobium hirsutum may be compared with the smaller—E. parviflorum.⁶

I find also that small flowers (dwarfed by lateness of blossoming?) of Eschscholzia californica, expanding in water, developed a profusion of pollen-tubes.⁷ Whether this is normally self-fertilising or not I do not know.

I hope next year to try a number of experiments protecting suspected self-fertilisers:—

Trusting you are enjoying better health than formerly | believe me to be | y^rs very truly | Geo Henslow