Tristan da Cunha flora.

Aquatic plants.

Density and diversity of plants in small plots in Kent, Keeling Islands, and Himalayas.

CD’s predicament with continental extensions: they would remove argument for multiple creations, yet he opposes the doctrine. Lyell will not express an opinion on this.

Lyell fears mutability would lead to more specific names.

Encloses copy of letters to Lyell [1910 and 1917].

JDH’s arguments against transmutation: 1. Plants do not show the confusion he would expect; 2. Under clearly similar physical conditions we do not find same species.

JDH’s argument against migration: commonality of alpine species. Believes migration opposes facts of botanical distribution in Van Diemen’s Land and New Zealand; prefers continental extension theory.

Agrees that Lyell’s letters shed no new light on extensions issue. Continental extensions: opposes their being hypothesised all over world.

Commonality of alpine plants damns both extension and migration.

Antarctic plants most difficult to account for on any theory. Lyell’s iceberg transportal of seeds.

Are there more representative species of American origin in Tristan da Cunha than in Kerguelen land?

Whether or not there should be movement of particles according to Tyndall’s theory of glacial action ["Observations on glaciers", Not. Proc. R. Inst. G. B. 2: 54–8, 441–3].

CD subscribes to H. C. Sorby’s view of gneiss [Edinburgh New Philos. J. 55 (1853): 137–50].

Seed-salting.

Pigeons.

Significant differences in skeletons of domesticated rabbits.

Will send MS on one point of geographical distribution. It is "of infinite importance" that JDH see it, for CD has never felt such difficulty in deciding what to do.

Wants capsules of aquatic plants, to float in sea-water.

Agrees with JDH that Cytisus report [presumably of a large change] not sound. CD pleased because, if true, species would change too quickly.

CD coming to London.

Read JDH’s review [Hooker’s Kew J. Bot. 8 (1856): 54–64 et seq.] of Alphonse de Candolle’s Géographie botanique raisonnée [1855] long ago.

Note accompanying MS of part of chapter 11 ["Geographical distribution"] of Natural selection [1975].

CD sorry he had to leave the Hookers abruptly to catch his train.

JDH approves MS section on geographical distribution.

Never felt so shaky about species before.

His objections to some mechanisms of distribution that CD proposes.

CD relieved by JDH’s positive response to his MS.

CD continues observations on means of transport.

JDH’s Raoul Island paper [J. Linn. Soc. Lond. (Bot.) 22 (1857): 133–41], showing continuity of vegetation with New Zealand, best evidence yet of continental extension.

CD finds JDH’s objections to a mundane cold period significant, and he endeavours to show how they do not rule out mutability.

He is writing on crossing.

JDH not happy with CD’s explanation of the absence of north temperate forms in the Southern Hemisphere, given his explanation for the spread of sub-arctic forms to the south. [CD’s note is in response to JDH’s criticism.]

CD encloses letter from Asa Gray, although it is critical of JDH.

Role of struggle in forming species in retreat from advancing glaciers.

Continued debate on formation of species as a result of retreat from glaciers.

JDH suggests internal powers of species modification, which he knows CD abhors.

CD, attempting to clarify debate, states more of his position. External conditions cause "mere variability". Formation of species due to selection. Relation of an organism to its associates far more important than external conditions.

Podostemaceae flowering under water.

Sends JDH part of MS for chapter 3 of Natural selection ["Possibility of all organic beings crossing"] to be corrected and returned.

JDH’s report of Podostemon flowering cleistogamously under water in Bengal.

[Copious revision by JDH.]