Sept. 20, 1883] 



NA TURE 



487 



full references to the works in which each genus has been 

 first described or best illustrated, with similar references 

 to the authorities for synonyms, add further to the value 

 of the work as a guide to the student of systematic 

 botany. 



The descriptive characters of the genera have been 

 throughout verified or established after the previous exa- 

 mination of numerous specimens, and as a rule it may be 

 said that for the purpose of this work the whole of the 

 vast collections in the Royal Herbarium at Kew were 

 passed in review, and especial attention given to the 

 aberrant forms presented by many large genera. In the 

 comparatively few cases where the authors were unable 

 to refer to and examine specimens of a genus enumerated, 

 they are careful to cite the author on whose authority it 

 has been admitted. Genera that appear to the authors 

 to have been founded on insufficient characters, or on an 

 erroneous view of the structural facts, are in some cases 

 reduced to the rank of subgenera or sections of the typical 

 genus, in others simply recorded as synonyms at the con- 

 clusion of the description of the genus to which they are 

 referred. There remains a further category of generic 

 names given by authors who, either from ignorance of the 

 science or incomplete materials, have failed to make it 

 possible to identify them at the present day. These are 

 enumerated as Genera dubia at the end of the synoptic 

 table of the genera of each family. In short, it may be truly 

 said that the authors have neglected nothing that could 

 make their work useful and practical, as well as a complete 

 storehouse of the present condition of our knowledge of 

 this branch of natural science. 



Of the many different points of view in which this great 

 work may be regarded, the most interesting, perhaps, to 

 the scientific naturalist is the consideration that we have 

 here the results of a complete reconsideration of the whole 

 subject of the classification of the flowering plants by two 

 men of remarkable intellectual power, possessing an 

 extent of knowledge and a command of materials far sur- 

 passing anything possible to the authors of preceding 

 works of similar scope. In one or two brief sentences of 

 a note already cited, Mr. Bentham has assigned the 

 amply sufficient reasons which induced the authors to 

 maintain in its main features the arrangement of the 

 natural orders established by the elder De Candolle. 

 Every attempt to set forth in a linear series the complex 

 relations which connect together as in a network the 

 various groups of the vegetable kingdom is necessarily 

 incomplete and defective. It is a fortunate circumstance 

 that the authors of the " Genera " have added the weight 

 of their authority to the judgment of those botanists who 

 hold that no one of the various arrangements which have 

 been proposed during the last half century, and more 

 or less extensively adopted in some parts of Europe, pos- 

 sesses advantages which can compensate the serious 

 practical inconvenience of having systematic works of 

 reference arranged after a variety of discordant systems. 

 The Candollean arrangement has therefore been delibe- 

 rately maintained in this work, with a few not unim- 

 portant modifications ; but in the arrangement and 

 grouping of the genera into tribes and subtribes there 

 has been ample space for the exercise of the highest 

 faculties of the philosophical naturalist. It is evident 

 throughout the work that every question as it has arisen 



has received fresh consideration, and in many important 

 families the classification adopted is altogether new. It 

 is remarkable that, even in regard to families previously 

 elaborated by Mr. Bentham, he has not hesitated to 

 introduce important changes suggested by further con- 

 sideration and study. It is of course impossible to say 

 that the final results of future discovery and research may 

 not lead to further modifications in botanical classifica- 

 tion ; but for the present generation this will remain as 

 the best result of the comprehensive survey of the whole 

 field of our knowledge. 



The number of genera described in the present work, 

 taking into account the addenda, is 7565, while the 

 number described by Endlicher in his " Genera Plan- 

 tarum," with the supplements, is 7202. These figures 

 give some measure of the progress of botanical discovery 

 during the last thirty years, and at the same time some 

 indications of the amount of labour involved in the col- 

 lection and examination of the materials scattered through- 

 out the numerous general works and monographs pub- 

 lished during that period, and especially throughout 

 hundreds of volumes of scientific periodicals which are 

 now annually produced in even- part of the world. The 

 increase in the number of known genera is in truth much 

 greater than the figures above cited would indicate, 

 inasmuch as the tendency of Bentham and Hooker is 

 to unite under the same generic designation plants which 

 do not appear to present sufficient differences of structure, 

 and they have not hesitated to suppress numerous genera 

 that have been admitted in preceding systematic works of 

 authority. Those who may not be disposed to acquiesce 

 in these conclusions may easily continue to regard as 

 genera the subgenera and sections whose distinctive cha- 

 racters are throughout the work subjoined to the descrip- 

 tions of the respective genera. 



It follows from the preceding remarks that for practical 

 use in classing large botanical collections the present 

 work is an indispensable guide. The present writer, who 

 has enjoyed the advantage of daily, almost hourly, reference 

 to its pages, feels that he is merely discharging a debt 

 of gratitude in endeavouring to express his sense 

 of the scientific value of a work which has become a 

 classic from the day of its publication. A work which, at 

 a given period, summarises the entire field of knowledge 

 in one department of science, marks an epoch in its 

 progress, and becomes the starting-point for further 

 advance towards wider knowledge. Such is the work to 

 which Mr. Bentham and Sir Joseph Hooker have devoted 

 a full quarter of a century, and as such, notwithstanding the 

 importance of their other works, it must remain their chief 

 title to enduring fame. Ern. Cosson 



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The Red Spot upon Jupiter 



The red spot on Jupiter has really disappeared. I have ob- 

 served the planet again after conjunction. The region in which 



