Remarks on the influence of pollen of one species or variety on the seed and fruit of another while still attached to the female plant. Refers to a remarkable case previously given by D. Beaton and asks whether Beaton will repeat the details.

[CD’s letter is followed by notes by D. Beaton in which he answers CD’s question, dissociating himself from some of his remarks, and in particular denying C. F. v. Gärtner’s claim that colour of one variety of pea can be changed by the direct action of the pollen of a different variety.]

Discusses the ill-will between England and U. S.

Considers the bases for deciding which plant species are "high" and which "low".

Comments on Alphonse de Candolle’s paper on oaks ["Étude sur l’espèce", Ann. Sci. Nat. (Bot.) 4th ser. 18 (1862): 59–110].

Encloses S. H. Scudder’s letter on Lepidoptera and fertilisation of orchids which identifies a butterfly with Platanthera pollinia adhering to it. Jokingly applies natural selection to butterflies acted on by orchid pollinia.

Informs JW that JH has received notice from H. J. Temple [Lord Palmerston] that Thomas Maclear is to be put on the next list to receive a pension.

Has received letter from Lord Palmerston [Henry John Temple] approving JH's request for a memorial for Thomas Maclear.