Taking another tack, from its smoothness, we might say, T. glabra or T. lævis; or, as I believe you have not a strong beard, T. imberbis. But, on the whole, perhaps it would be as well to indicate merely the nearest affinity of the genus, and call it “Thurberia thespesioides,” as it is nearest Thespesia. Take your choice, though, of any of the above, to which add “T. rosea,” if the color of the flower warrants that name. TO A. DE CANDOLLE. CAMBRIDGE, June 1, 1854. MY DEAR FRIEND,--It was with great pleasure that I received from you, two days ago, your letter of the 2d May. I counted myself your debtor, although, indeed, my last letter of 18th October is of later date than yours of the 1st October, which it crossed on the ocean, and I was only waiting until I could announce a small envoi to you, namely, that of a copy of the 1st volume of the “Botany of the United States Exploring Expedition in the South Seas,” which has been more than a year in printing. This 4th volume (777 pages) is at length happily printed off, and just in time, too, for sending you a copy (unbound, direct from the printing-office at Philadelphia) in the annual envoi of the Smithsonian Institution. The atlas, of 100 plates in folio, which should accompany this volume, is by no means ready, owing to the slowness as well as the feeble health of the artist, Mr. Sprague; perhaps, even, it may not reach you before next year, by the same mode of conveyance. I have now, indeed, some hopes that the “Flora of North America” may soon be carried through the Gamopetalæ, I elaborating at the same time, in a general memoir, the Gamopetalæ of Wright’s, Fendler’s, and Lindheimer’s collections in continuation; a pretty formidable matter! In a separate small parcel you will find (in the Smithsonian envoi) some brochures for you.... Among them is a short article in “Silliman’s Journal,” accompanying a reprint of a great part of Dr. Hooker’s Introductory Essay to the “Flora of New Zealand.” Agassiz here is committed to the view opposite to Hooker’s, in an equally extreme form. I wished to interpose some criticisms to both views, but had only time to touch briefly on one or two points. I wait with impatience for your work on “Géographie Botanique,” expecting very much from it, from your great ability, long study of the subject, and fairness of mind. Indeed, I was daily expecting to learn that it was published; and now you tell me that the printing is barely begun; the “Prodromus,” volume 14, not yet begun! But I am one of the last persons who ought to complain of delay in execution....