To Asa Gray   16 December 1879

My dear Gray

It is uncommonly good of you to have taken so much trouble about the seeds; but it makes me feel rather guilty, for though I was very curious to see them germinate, yet the points in question were not of much importance.¹ Ipomœa leptophylla has not yet germinated, but I have a good many seeds to sow again in the early spring, if those already sown do not germinate; & I have often suspected that some kinds of seeds have an obstinate inherited habit of not germinating & dying if sown in the winter.— I have just put 5 of the seeds of Megarrhiza to soak, but only one sinks & this alarms me.— I very much want to see whether the curious heel-like projection at the base of the hypocotyledenous stem, described by Flahault, & which splits the seed-coats so beautifully in other Cucurbitaceæ, is here absent, as I hope & as ought to be the case as the Cotyledons are not with-drawn from the seed-coats.²

Now do not waste your very valuable time, but if you c^d. easily send me a score of seeds of the common cotton, (Gossypium), I sh^d. be glad; for oddly enough I can get no seeds in England. They have written for me to abroad from Kew, but seem doubtful of the result.— The cotyledons behave oddly at night, for when old & only when old they sink downwards, & I did not when I had seedlings investigate the point sufficiently.³

Ever yours very truly | Ch. Darwin