From Peter Henderson   15 November 1876

Mr Charles Darwin, Dear Sir,

I am the writer of a book for Amateurs in Gardening, a copy of which I mail you today, at page 47. you will observe I take the liberty to combat your views on the subject of “Graft Hybrids”,¹ in reading your remarks on the subject however, I omitted to notice your allusion to the case of Cytisus Adami, which is claimed to be a “graft hybrid”, between C. Laburnum and purpurea. This case would seem to have been the most marked one on record in favor of the theory of “graft hybrids”,² but unfortuneately for that beleif, but fortunately, perhaps, for truth I have found a gentleman, William J. Davidson, (who is Recording Secretary of the Horticultural Society of New York)³ who asserts most positively that thirty years ago he saw, a tree of Cytisus Laburnum, upwards of fifteen feet in height, from the topmost branches of which a branch produced purple flowers, The tree had never been budded or grafted, a most ridgid examination made certain, so that here it would appear there was no other explanation for the anomaly than what you so aptly call “bud variation”, which all large cultivators see in hundreds of different species in one form or another— Why then may not the Cytisus Adami have also been a bud variation, instead of a so-called “graft hybrid”— I may state that Mr Davidson the gentleman who is my authority for the above is an excellent Botanist as well as a Practical Horticulturist of most extensive experience, and a man of strict integrity— A Lady friend Mrs Hanaford, who is one of my neighbours, wrote to you that I was experimenting with Dionea to test the insect eating theory, I will be glad to inform you of the results when that Experiment is completed.—⁴

Very respectfully yours | Peter Henderson