Has named 35 species of grasses.

Seed-salting continues.

Thanks JSH for seeds.

Clarifies his request about marking [London] catalogue [of British plants] – JSH is to mark those he thinks really are species, but which are very closely allied to some other species.

Australian Leguminosae problem: of 900 species not ten are common to southwest and southeast. No migration; hence either creation or variation.

Himalayan thistles: graded intermediates between large and small English species, "shakes species to their foundations". Similarity of CD’s and his views on species.

Asks for advice on establishing a control group in his experiments to produce sports and varieties of Lychnis diurna.

Seeks seeds of wild Dianthus for hybridising and producing varieties.

Returns CD’s list of Azores plants with information on the distribution of the species added. Encloses a list, extracted from CD’s list, of those plants common to Europe and the Azores that were probably not introduced by man.

Sends a list of 22 plants that grow at Hitcham and in the Azores and are, according to H. C. Watson, least likely to have been imported [by man]. Will pay the little girls of Hitcham liberally to collect the seeds for his experiments.

CD experiments: sowing seeds in fields; "breaking" seeds’ constitution with coloured light; plant hybridisation. Compiling works on hybridism.

Respect for W. B. Carpenter.

Note on "nectar secreting" to Gardeners’ Chronicle [Collected papers 1: 258–9].

Has read a paper, presumably by JDH, using the Madeiran flora to argue against Forbes’s doctrine.

JDH asked how far CD will go in attributing common descent; he intends to show "the facts & arguments for & against the common descent of species of same genus; & then show how far the same arguments tell for or against forms, more & more widely different".

Parcels sent to Down by coach may get lost.

Discusses how best to simulate the light at a particular point on the earth’s surface using coloured glass; considers sunlight as composed of three "principles", varying in proportion according to latitude, which affect germination, lignification, and floriation.

Congratulations to JL on finding musk-ox fossil.

Thanks JSH for all he has done. His botanical little girls are marvellous. His marking of the list of dubious species is what CD wanted. Explains that he wanted to ascertain whether closely allied forms belong to large or small genera.

Invites JSH to dine at CD’s brother’s house in London.

Informs CD which colours of glass accelerate germination, lignification, and floriation; advises CD on obtaining such glass and offers his help in any experiments.

Delighted JSH can dine. Has invited Hooker.

Thanks him for Lychnis seed.

Asks for umbel of wild celery. Wants to ascertain whether wild or tame plants produce most seed.

Praise for JDH’s Flora Indica [J. D. Hooker and T. Thomson (1855)] from CD and C. J. F. Bunbury.

CD and J. S. Henslow dining in London. JDH invited.

Sends a skeleton of a Bengal jungle cock.

Has never heard of trained otters breeding in captivity.

Introduced domestic rabbits are confined to the ports of India.

Canaries and other tame finches and thrushes brought into India do not breed well.

Origin of the domestic canary. Tendency of domesticated birds to produce "top-knot" varieties.

The tame geese of lower Bengal are hybrids; those of upper Bengal are said to be pure Anser cygnoides.

Wild Anser cinereus occur in flocks in the cold season.

Discusses at length different breeds of domestic cats and possible wild progenitors. Wild and domestic cats occasionally interbreed. The Angora variety breeds freely with the common Bengal cat and all stages of intermediates can be found.

Believes pigeons have been bred in India since remote antiquity.

Discusses whether mankind is divided into races or distinct species.

[CD’s notes are an abstract of this letter.]

Morning with H. C. Watson; discussed problems of inferences from buried seeds.

Gives names of German dealers who provide seed of superior quality.

Is having difficulties marking close species on the list of British plants.

In all his attempts to advance geographical botany he is stopped by the "application and signification of the word ""species"" " the use of which is both "indefinite and variable". He encloses his list of "Categories of Species".