Letter number 17 written by Charles Darwin

RELATING A NEW DISCOVERY. DARWIN, CHARLES. Autograph Letter Signed, "Ch. Darwin," to Shropshire naturalist W. A. Leighton, a lengthy letter discussing botanical findings, including differences in hairs on an unnamed fruit, experiments with Primula, and his accidental discovery that movement of sepals causes the corollas to detach from Verbascum. 8 pages, four 8vo sheets; remnants of prior mounting on the left edge of the first page, usual folds, a bit toned. Down, 4 December [circa 1861]

" . . . I had a Verbascum in my garden (which I now know to be a natural hybrid from V. thapsus & lychnites) & I wished to make some experiments on it; so I asked Mrs. Darwin to come & tie in thread the quite young flowers. To do this she had with forceps to pull off buds on each side. When I came to fertilise them, I cried out 'Why have you chosen old flowers & the corollas are all dropped off?' She declared she had not & tied some more & when I came I found them also all off. So I said we will make sure this time for we will pull each flower and see the corolla is firm; so we again pulled off the buds on each side & tied the thread, when lo & behold off dropped all the corollas. It is caused by the movement of the sepals . . ."