Thanks GB for his help on naturalised plants; comments on spreading of plants.

Wants to quote GB on the names of species and varieties of Silene on which C. F. von Gärtner experimented.

Thinks GB will be disappointed in his book [Natural selection]. "It will be grievously too hypothetical."

Discusses the relative growth of native and foreign weeds.

News of Mrs Henslow’s death.

Studying Impatiens, which bears on CD’s problems. Though genus is endemic to India, with over 100 species, CD will be glad to know they do not run into one another.

Inquiries on effect of dry heat on temperate plants for glacial chapter.

Finds CD’s results [of his survey of well-marked varieties from A. P. and Alphonse de Candolle’s Prodromus systematis naturalis regni vegetabilis (1824–73)] "very curious and suggestive". Thinks the Labiatae will present an obstacle to him as it is a very large and distinct order with well-defined species and genera. Would like to see him tackle more volumes of Candolle’s Prodromus, as his case can only be established by evidence from mundane plants. CD should beware of generalising from local species variability. A comparison of C. C. Babington’s and G. Bentham’s [British] Floras [Babington Manual of British botany (1843, 4th ed., 1856); Bentham Handbook of British flora (1858)] would be invaluable. Suggests CD write to Ferdinand Müller and Charles Moore in Australia. Moisture favouring extension of species is important for CD’s view.

No summary available.

Asks whether British or north European perennial plants can, under cultivation, withstand the climate of S. Australia.

Acknowledges receipt of £248 2s. 1d.

Survey of species with well-marked varieties: JDH’s Labiatae case a "great blow", but result is very generally consistent.

Thanks for offer of pigeons, if breeding is successful; hopes to go to poultry show to see them.

Several questions about the Boz or Booz pigeon of Tunis.

If any of EWVH’s birds die and he does not want the skin, perhaps he would send it to CD.

Will shortly return CD’s list of varieties of British plants. Discusses the situations in which different varieties of species are often found and the ranges of varieties relative to those of the species.

For his studies on fertility of crosses, asks GB to mark a list of pairs of Cucubalus as to whether they are varieties of the same species, or distinct species.

Will not accept invitation to Hastings, or offer to send pigeons to Down.

Is looking forward to seeing pigeons at Crystal Palace poultry show.

Returns CD’s lists [sent with 2184]. Confusion in genera of Silene is great in continental botanic gardens. One would have to know whether C. F. v. Gärtner had the right names for species in his experiments.

THH’s catalogue [THH and R. Etheridge, A catalogue of the collection of fossils in the Museum of Practical Geology (1865), part published in 1857] best résumé he has seen of science of natural history. On classification he is not quite sure that he wholly goes along with THH. Encloses a few criticisms of THH’s preface.[enclosure survives as copy only].

Sending more Candolle volumes for survey of species with well-marked varieties.

Has begun his introduction [to Flora Tasmaniae]; will not make generalisations.

J. D. Dana’s pamphlet too metaphysical for JDH.

Thanks WDF for his letter about a rabbit breed that he thinks is the Himalaya. He is particularly glad to hear of it because it breeds so true.

Thanks GB for his answers [to 2184], which were as explicit as he expected. Cucubalus viscosus and italicus are extremely sterile together; all other forms extremely fertile. Other instances of infertility found by Gärtner.

Hybrid varieties of pheasant and common fowl. Reply to CD queries.

Finds he cannot annotate CD’s list of subspecies and varieties as wanted. Mentions again his difficulties with "species"; he "cannot find the proof of species being definite and immutable whatever they may seem to be at any one time and spot".