If time (which is now precious to me) permit, I will write a series of articles on it for “Silliman’s Journal,” which will serve to make the work generally known to our people, and in which I can insert any commentaries I have time and room for. One article I will devote to plants introduced into this country from Europe. Now that you have so well collected and digested the principal information, it will be easy to complete and correct some points; and this may be useful to you hereafter, as well as to me.... I will procure from Dr. Harris any information he has collected about the potato, which, if Raleigh took it from Virginia to England, must have been brought to Virginia from South America. It was certainly unknown to our aborigines, who, however, along with maize, cultivated beans (Phaseoli) and squashes (Cucurbitæ). Dr. Hooker had written to me, eulogizing your work in the highest terms. I missed seeing him when in England. Agassiz speaks most highly of it; but I think he has only looked rapidly through its pages as yet.... I am at this moment preparing to begin the printing of the 2d edition of my “Manual of the Botany of the Northern States.” ... In consequence of your book, I shall take pains to classify the introduced plants, according to the degree of naturalization, etc. Many thanks for sending me your portrait. I am already quite rich in the likenesses of botanists, many of which adorn the walls of my apartments.... Believe me to remain, my dear friend, yours very faithfully and truly, ASA GRAY. TO W. J. HOOKER. CAMBRIDGE, February 25, 1856. MY DEAR SIR WILLIAM,--Holton is bringing out a book upon New Granada which will be interesting.... The cypress knee sent was the best and handsomest I had, though not the largest. I am glad it pleases you. But you mistook what I said, or meant to say, which was, that tucked away in the hollow you would find placed a specimen of a forming knee, not much bigger than your knuckle, on a piece of root a foot or so long. Was this overlooked or lost? Please tell me; for I can replace it with another, and physiologically it would be well to show the formation in its various stages.... I want to send you a book by a young friend of ours, Olmsted, on the seaboard slave States,[33] an admirable volume, full of information, and lively withal. I wait for an opportunity. Lady Hooker will be interested in it. Our united warm regards to her. Thanks to the Duke for anything to facilitate transmission of printed matter. But it is still high; for example, your “Journal,” which I get by post, costs 6d. each number, paid in London, and about 1d. more paid here. There is still room for improvement. I dare not send you “Silliman’s Journal” yet by post. June 30, 1856.