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 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with his Father [William Jackson Hooker], who can be stuck in old ways of thinking, JDH stops him from publishing outdated views.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]