Discusses difficulties involved in deciding which genera are protean in the light of some comments by H. C. Watson.

Thanks for AG’s remarks on disjoined species. CD’s notions are based on belief that disjoined species have suffered much extinction, which is the common cause of small genera and disjoined ranges.

Discusses out-crossing in plants.

Has failed to meet with a detailed account of regular and normal impregnation in the bud. Podostemon, Subularia, and underwater Leguminosae are the strongest cases against him.

Believes, with CD, that extinction may be an important factor in explaining plant distributions, but sees no reason why the several species of a genus must ever have had a common or continuous area. "Convince me of that, or show me any good grounds for it … and I think you would carry me a good way with you". It is just such people as AG that CD has to satisfy and convince.

Feels that the crossing of individuals is important in repressing variation and perhaps in perpetuating the species, but instances some plants in which it cannot, apparently, take place.

Believes species have arisen, like domestic varieties, with much extinction, and that there are no such things as independently created species. Explains why he believes species of the same genus generally have a common or continuous area; they are actual lineal descendants.

Discusses fertilisation in the bud and the insect pollination of papilionaceous flowers. His theory explains why, despite the risk of injury, cross-fertilisation is usual in the animal and vegetable kingdoms, even in hermaphrodites.

States he has "misgivings about the definiteness of species". Believes there is some inherent tendency for plants to originate varieties. Cross-fertilisation is likely in most cases but sees difficulties with plants like Adlumia.

Encloses an abstract of his ideas on natural selection and the principle of divergence; the "means by which nature makes her species".

Discusses varieties and close species in large and small genera, finding some data from AG in conflict with his expectations.

Has been observing the action of bees in fertilising kidney beans and Lobelia.

Thanks AG for his criticisms of CD’s views; finds it difficult to avoid using the term "natural selection" as an agent.

Discusses crossing in Fumaria and barnacles.

Has received a naturally crossed kidney bean in which the seed-coat has been affected by the pollen of the fertilising plant.

Finds the rule of large genera having most varieties holds good and regards it as most important for his "principle of divergence".

Asks whether botanists tend to record varieties more carefully in large genera or small genera.

Wants information on the ranges of varieties of a species compared to the range of the species.

List of close species taken from AG’s Manual of botany [1848].

Discusses the variation of species in large and small genera.

Thanks AG for his list of close species.

Laments the slow progress he makes with his book [Natural selection].

Self-fertilisation in Fumariaceae.

[CD note on bees’ visiting some members of Fumariaceae.]

Believes that, in Dicentra, Fumaria and Corydalis, flower structures are related directly to visits from bees. Flower stigmas generally are placed in the path of bees.

Has received paper from Wallace on natural selection; has sent abstract of his notions, with Wallace’s paper, to Linnean Society.

Species migration since the Pliocene. Effect of the glacial epoch. Present geographical distribution, especially similarities of mountain floras, explained by such migration; mountain summits as remnants of a once continuous flora and fauna.

Cross-fertilisation in Fumariaceae.

Wishes to know whether differences in constitution (such as disease susceptibility) are related to differences in complexion. "Liability to such a disease as yellow fever would answer my question in the best possible way."

Sends copy of Origin for comments.

Does not feel AG’s views of migration after the last glaciation explain distribution in U. S. as well as CD’s view of migration prior to glaciation.

Would welcome American edition of Origin.

Thanks for AG’s Japan memoir [Mem. Am. Acad. Arts & Sci. 6 (1857–9): 377–452]. Does not think AG’s arguments for a warm post-glacial period are sufficient, but will not be sorry to be proved wrong.

Believes natural selection explains many classes of facts which repeated creation does not.

Writes of some responses to the Origin.

JDH thanks Asa Gray for his opinion on an unspecified essay by JDH, letter includes discussion of species & specific centres suggesting the subject of the essay is geographical plant distribution, the definition of a species & whether they are created entities or varieties evolve with environmental influences. JDH refers Gray to his comments in the FLORA ANTARCTICA. He argues against Gray & Agassiz's belief in multiple centres. Discusses the relative importance of genetic resemblance as opposed to habitat, referring to the Dorking Fowl, Manx Cats & Falkland Island rabbits. He favours theories based on observable evidence of geography, physiology etc. Dismisses Agassiz's work, incl on glaciers such as Aletsch, as prejudice not based in fact but on a desire for notoriety. JDH & Lyell like Agassiz personally. JDH looks to Americans for future discoveries in science as he considers them more practical. Bentham has decided to give his herbarium to RBG Kew. Thomas Thomson [TT] wants to be botanist on an expedition to North West Australia, if the East India Company will give him leave. Hurt approves of TT, who was imprisoned with his brother during the Afghanistan campaign. William Jackson Hooker has applied to The Duke of Newcastle on TT's behalf. Writes of progress with FLORA INDICA & distribution of plant sets to Gray, Paris, Berlin, Vienna, St Petersburg, Brown at the British Museum, Lowell & Torrey. Asks Gray about North American Larch, Yew, Junipers & Coniferae incl. Scotch Pine. Uses Yews from Pontrilas as an example of the difficulty of using habitat vs character in determining species. The Deodar Avenue at Kew is another example of how plants may not always have the ideal characteristics of their species. Agrees that species cannot be pronounced the same because they are united by certain forms, gives Mt Lebanon & Himalayan Cedars as example of extreme forms. Argues the difficulty is with local botanists wanting to give local varieties a distinct classification.

JDH thanks Gray for his critique of one of JDH's papers. JDH knows he is a difficult person when it comes to criticism. He mentions the issue of defining species & the significance of genetic resemblance & explains that he & Thomas Thomson have touched on the subject in the introduction to the FLORA INDICA. This long introduction will also include an account of the history of Indian botany, an essay on the climate & geographical account of the provinces. JDH is distributing & naming his Indian plants & laments the lack of standard nomenclature. He is currently working on Antidesmas with reference to Tulasne's paper, which is imperfect because of the shortcomings in the French collections he consulted. He mentions the difficulty in pinning down the characteristics of wild & cultivated Yew. JDH has taken a house on Kew Green for George Bentham, near William Jackson Hooker's herbarium in Hanover House. The herbarium now has a curator. Sometimes JDH thinks of abandoning Kew to write for the press in London, he finds it hard to support his growing family on a government salary whilst living in expensive Kew. JDH's father WJH is trying to secure JDH's continued employment for the Office of Woods & Forests but JDH is not optimistic. JDH stays at Kew to please his father & to have access to his herbarium & library. Nathaniel Wallich is very ill, Brown better at present. The Van Diemen's Land [Tasmania] Government have purchased 6 copies of JDH's forthcoming FLORA TASMANIAE & the income is welcome as he made no money from his Antarctic expedition southern floras. JDH describes his recent work on fossil plants, especially Trigonocarpi from coal formations, they resemble Salisburia. JDH outlines his responsibilities regarding scientific societies, he is on the council of the Royal, Linnean & Geographical societies. He has managed to secure a review of the state of the Linnean Society botanical collections. Mentions Caspar Georg Carl Reinwardt is dead at Leyden [Leiden].

JDH thanks Asa Gray for his note of 10 Mar [1857]. Is impatient for LESSONS, apologises for not reviewing the MANUAL in the JOURNAL OF BOTANY. William Jackson Hooker wants JDH to review [Miles Joseph] Berkeley's INTRODUCTION TO CRYPTOGAMIC BOTANY, JDH praises its content but calls it 'appallingly written & arranged', a common failing of parson-authors such as Sedgwick & Buckland, Copewell[?] & Baden-Powell. An abstract of the Linnean Society's ideas on genera will appear in the LITERARY GAZETTE & a summary by Bentham in the Linnean journal. JDH is critical of the way Germans approach a subject, A. Braun's work on genera is an exemplar. JDH dismisses [Berthold Carl] Seemann's 'twaddle' about genera being objective or subjective, gives Rosa & Salix as examples of the former & Unbellifers as the 'confoundedly bad' latter. Discusses [Thomas] Thomson's paper on germination & embryos of Careya & Barringtonia. JDH worries about Gray doing a book on forest trees. Notes [Richard] Spruce is stranded in Tarapoto, in the Andes, en route to Lima. Mentions UK government expedition to the source of the Missouri & the East Rocky Mountains, [Eugène] Bourgeau is the botanist & the commander Mr Palliser. JDH's children & wife [Frances Hooker] are in Brighton. JDH suggests a visit to the UK would stimulate Gray's work on the Flora of North America. [Walter Hood] Fitch has produced plates of British natural orders, designed by [John Stevens] Henslow, for the National Schools under the Board of Trade. In a post script dated 30 Mar JDH gives a detailed opinion of Gray's ELEMENTS. JDH cannot visit Canada & USA until 1858, he has too much work, with the Indian Herbarium & Tasmanian flora for the Van Diemen's Land government, & not enough money. Comments briefly on Gray's notices in SILLIMAN & at length on De Candolle's botanical geography, referring to the work of de Heer, Henfrey, Brown, Forbe's Atlantis theory & Duchastre's encyclopaedia. Recommends that Gray get the GARDENERS' CHRONICLE.