use of his private library and herbarium, and asking his co-operation in the series of colonial floras then projected at Kew), averted this threatened loss to science. Bentham returned in 1855 to London, and from 1861 onwards lived at 26 Wilton Place, and almost daily, except during excursions to the continent or to Herefordshire, went to Kew and worked at descriptive botany from 10 a.m. to 4 p.m. To his assiduous labours are due the 'Flora of Hongkong' (1861), a model of its kind, and the 'Flora Australiensis,' including seven thousand species, the most extensive exotic flora ever completed, and the unrivalled 'Genera Plantarum.' The working up of the vast and peculiar flora of Australia at such a distance from the localities would have been much more difficult but for the abundant and capable aid afforded by Baron F. von Müller from Melbourne, and the specimens which he transmitted. Nevertheless the work was enormous to undertake single-handed, and Bentham's fears lest he might not live to complete it are very intelligible, when we learn that his success involved the personal examination, criticism, and description of from one thousand to twelve hundred species in a year, as well as the consultation of authorities respecting them. The publication of this great 'Flora,' in seven octavo volumes, extended from 1863 to 1878. The preface gives a vivid idea of the extent of the labour which was expended upon it. Bentham further drew up terse and valuable 'Outlines of Botany,' to be prefixed to all the colonial floras.
Meanwhile the Linnean Society realised Bentham's value as an administrator, and elected him vice-president in 1858, and president in 1861, which office he held continuously for thirteen years with very great success. Time, thought, and money were unsparingly devoted to the promotion of the society's interests, and he was practically secretary, treasurer, and botanical editor as well as president. He personally rearranged the society's librarv on its transference to the new buildings in Burlington House. Bentham's annual presidential addresses were of a masterly character, whether they dealt with philosophical subjects or with the progress of botany. His cautious temperament and logical method made his adhesion to Darwin's views of evolution of great value, when in 1863 he declared that the accuracy of Darwin's facts was no longer contested, and that much of his reasoning was unanswered and unanswerable. In 1868 he thus formulated the principles which he also consistently practised. 'In every biological undertaking . . . there is one true course to pursue: first, to observe for one's self once and again, and to test personally the observations of others; secondly, to collect, compare, and methodise all that has been published and authenticated upon the . . . subject of investigation; and thirdly, to reduce the observations to a general treatise, and speculate upon the conclusions to be drawn from them.'
His valedictory address to the Linnean Society appears in the British Association Report for 1874 as a 'Report on the Recent Progress and Present State of Systematic Botany,' of high historical and autobiographical value. It also, like some of his Linnean addresses, indicates in detail the work remaining to be done in botany.
Bentham's most conspicuous achievement, however, is his share, the larger portion, in the 'Genera Plantarum,' which occupied more than the last quarter of a century of his life. An account of the portions of the work done respectively by Bentham and Sir Joseph Hooker has been given by the former (Linn. Journ. Bot. xx. 804; see also Nature, xxviii. 486). The first part appeared in 1862, and the first volume was completed and brought up to date in 1867; the first half of volume ii. was issued in 1878, the second half in 1876; the first part of volume iii in 1880, the concluding portion in 1888. A single incident may serve to indicate the spirit in which Bentham worked. After more than a year's constant and uninterrupted labour on the orchids, he concluded his revision of that difficult order late one Saturday afternoon; but without pause, knowing that the grasses, a still more arduous task, remained to be undertaken, he simply bade an attendant bring him the material for commencing this last great portion of his work, and immediately began. A man of this mould seemed destined to complete what he undertook, octogenarian though he then was; and the 'Genera Plantarum' gives a revised definition of every genus of flowering plants, a view of its extent, geographical distribution, and synonymy, with references and notes. The Rev. M. J. Berkeley revised the Latin text to secure uniformity of style and diction. The descriptive characters of the natural orders are most carefully drawn up. Nothing has been neglected which could add to the value of the work. The authors have personally examined specimens, living and dead, of the whole series of flowering plants wherever practicable, their extent of knowledge and command of materials far exceeding anything previously attained. The Candollean arrangement of orders is maintained for the most part, but nearly every important order is remodelled. Such a work
