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 letter & review of [Rev. Miles Joseph] Berkeley. Berkeley will not like Gray's review or JDH's in JOURNAL OF BOTANY. JDH comments on Gray's criticism of his ideas on physiology, comparing them to a firework, and to his own less ordered style of critique. Declares that he will not take account of a 'vital force' until anyone else does. Compares American & British terminology i.e. in the United States physiology is synonymous with biology. Discusses nomenclature & the use of the English 'anth' in names such as Ranunculanths, compared to using the suffixes: 'ads' or 'worts' in place of aceae. This was started by [John Stevens] Henslow & despite misgivings JDH has advised [George] Bentham to retain them as they are now effectively sanctioned by the government; being used in the National Schools. He asks Gray not to deter Bentham from using the system as it is the current vogue & it is hard enough to get government to publish such books for the amateur, & this class of people cares a great deal about terminology. JDH thinks [John] Lindley is correct to refer Podostemons to near Lentibulariaceae though he previously thought their place was with Scrophulariaceae.

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.

JDH characterises himself to Asa Gray as a full throated critic. He often disagrees with his Father [William Jackson Hooker], who can be stuck in old ways of thinking, JDH stops him from publishing outdated views. They clashed over the JOURNAL [OF BOTANY] work, JDH is glad it is discontinued. JDH offers Gray species of Rubiaceae, he might bring them himself if he goes to the USA this year. Has consulted Huxley re. Gray's notes on vitality & offers his comments. Discusses his thoughts on dedoublement, at length, he has discussed the theory with [George] Bentham[GB] & does not consider it logical. Mentions Gray's work on Balanophoreae. Discusses in detail Dicotyledonous exogens & the hierarchy of flowering plants, enumerating the characteristics which should define the highest type. He thinks that the 'vegetable ladder' should be arranged by physiology of the reproductive organs with organic complexity secondary: this would elevate gymnosperms above Phaenogams. [Arthur] Henfrey has found the corpuscula[?] in Gnetum, he suspects the seeds take 7 years to ripen. JDH describes the development of Gnetum ovule during fertilisation. JDH is working on East India Company Assistant Surgeon competitive examination papers & Royal Society Report for [David] Livingstone's expedition. Comments that Gray has correctly described Sambucus fruit. Describes his observations on ovules in different plant genera & families: Viburnum, Caprifol[iaceae]. Conv[olvulaceae]. Aral[iaceae]. Umbelli[ferae]. Rubiaceae, with particular reference to raphe in Lonicerae. He suspects ovule structure will lead to affinities. He discusses his study of Chimonanthus, which he places nearer Monimiaceae & Annonads than Rosaceae, calycifloral characteristics being key. JDH thinks Cumming's Morinda is new. He is sending a fruit of Ceylon [Sri Lanka] Eupyrena. GB recommends his notes on Rubiaceae. Gray could send his notes on Timonius to the Linnean journal, JDH has not received the proof of Gray's Magnolia paper.

JDH hopes Asa Gray continues his U.S. EXPLORING EXPEDITION publication. JDH is studying the flora of Fiji, Tahiti & the Sandwich Islands [Hawaii] & working on a preliminary essay to FLORA TASMANIAE. He is trying to trace the extent of Australian flora in the Pacific: it goes as far as New Zealand, Norfolk Islands, New Caledonia & the New Hebrides [Vanuatu] but no further, the flora of Fiji is more Indian. Possibly the explanation lies in differing geology. He thinks that an ancient Southern Continent must be the origin of the Australian flora & explanation for there being South African types in South West Australia & Polynesian species on the East coast of the continent. Discusses evidence of type persistence in Australia: Miocene era Banksia ericifolia preserved in lava beds in Victoria, & fossil Casuarina cones from Bass Straits. However, he also has an Araucaria excelsa cone from oolite in England. He concludes that geographical ranges have changed & the old theory of absolute creation is disproved & he will work to more modern hypotheses [Darwin's natural selection] without accepting them as doctrine. It must be accepted that the formation of land & sea has changed as agents of migration such as animals, wind & currents cannot account for current species distribution. He lists his five starting hypotheses to explain distribution of species, including the evolution of new species by selection & effects of land movement. Also, enumerates how this agrees with the expected fact of evolution of species from an aboriginal condition, including the existence of greater numbers of distinct species on remote islands & the great biodiversity of the southern temperate zone considering there is so little land compared to the North. JDH wrote these thoughts at Lord Wrottesley's, he has now returned to Kew & paid Thomson's[?] debt to [William Henry?] Harvey. JDH is shocked by Alphonse de Candolle begging to be made a Foreign Fellow of the Royal Society. [Letter incomplete]