Your last letter has gone to Engelmann, as I notified you; those of May 29 and June 4 overtook me in the mountains of North Carolina, where Mrs. Gray and I were recuperating, but I was kept on the move from morn to night. I could not thence write you on the matters treated of, nor is there anything left to say.... Nature sometimes does what you hit me for suggesting, that is, “take away the essential character,” and we have to put up with it, and allow that we may have overrated the character. But, when all is done, I will try on your view without prejudice, and adopt it if possible. About Ceratophyllum: I never followed up that early paper, of 1837, because I soon saw that I was very wrong in supposing that the ovules of Cabomba and Nelumbium were like that of Ceratophyllum, and I concluded that my whole idea was baseless. I have not looked at the matter since, but I shall be much surprised if you find that my youthful idea is worthy of resuscitation. We have come back from the cool mountains of the South to really hot weather at the North. TO A. DE CANDOLLE. CAMBRIDGE, July 15, 1879. MY DEAR DE CANDOLLE,--Your pleasant letter of the 3d June reached me on Roan Mountain, in a comfortable little house, at the elevation of about 6,200 feet above the sea, enjoying glorious views of range after range of the Alleghany Mountains, and on the grassy plateau Rhododendron Catawbiense, perhaps more of it than in all the rest of the world, just coming into blossom. Then the valleys and mountainsides all around, covered with rich forest, are adorned with Rhododendron maximum, and Kalmia latifolia in immense abundance and profuse blossoming, of every hue from deep rose to white, and here and there, among other flowering shrubs, Azalea calendulacea, of every hue from light yellow to the deepest flame color. Mrs. Gray was with me, with her brother, two nieces, and a botanical party consisting of Messrs. Canby, Redfield, and Sargent. We traversed a pretty large and very wild region, much of which I had before visited, some thirty-eight years before. We went to the locality of Shortia galacifolia, discovered by Hyams; but our search for new stations, or for the old one of Michaux, was in vain. But I have now a clear idea of the district in which it may be sought. The known station is probably one to which the plant has been brought down. I have returned home to a crowd of work.... I wait with great interest your volume on Phytography. You will see that in my new “Text-Book” we are quite in accord. I agree with you about new and useless terms, and the execrable taste of the Germans. I am very strong, and can climb a mountain as well as ever, only I lose breath except I move slowly in the ascent. Memory rather fails; otherwise I have at near sixty-nine all my faculties in fair condition. It has happened that I have visited Europe every eleven years. According to that you should see me next year! I cannot promise; but I am always affectionately yours,