314 SIR JOSEPH DALTON HOOKER 



work were the Genera Plantarum of Linnaeus (1737 1764) and 

 of Jussieu (1789), to which may be added that of EndHcher 

 (1836 1840). But all of these were written while the number 

 of known genera and species was smaller. The difficulty of the 

 task of Bentham and Hooker was greatly enhanced by their 

 wider knowledge. But their Genera Plantarum is on that 

 account a nearer approach to finality. Hitherto its supremacy 

 has not been challenged. 



The fourth of the great systematic works of Hooker men- 

 tioned above was the Index Kewensis. It was produced upon 

 the plan and under the supervision of Sir Joseph by Dr Daydon 

 Jackson and a staff of clerks. The publication began in 1893, 

 and successive supplements to its four quarto volumes are still 

 appearing at intervals. The expense was borne by Charles 

 Darwin. The scheme originated in the difficulty he had found 

 in the accurate naming of plants. For "synonyms" have fre- 

 quently been given by different writers to the same species, and 

 this had led to endless confusion. The object of the Index was 

 to provide an authoritative list of all the names that have been 

 used, with reference to the author of each and to its place of 

 publication. The habitat of the plant was also to be given. 

 The correct name in use according to certain well-recognised 

 rules of nomenclature was to be indicated by type different from 

 that of the synonyms superseded by it. The only predecessor 

 of such an Index was Steudel's Nonienclator Botanicus, a book 

 greatly prized by Darwin, though long out of date. He wished 

 at first to produce a modern edition of Steudel's Nonienclator. 

 This idea was, however, amended, and it was resolved to 

 construct a new list of genera and species, founded upon Bentham 

 and Hooker's Genera Plantarum. Sir Joseph Hooker was asked 

 by Mr Darwin to take into consideration the extent and scope 

 of the proposed work, and to suggest the best means of having it 

 executed. He undertook the task, and it was he who laid out 

 the lines to be followed. After years of labour by Dr Daydon 

 Jackson and his staff, the work was produced. But Sir Joseph 

 read and narrowly criticised all the proofs. Imagine four large 

 quarto volumes, containing in the aggregate 2500 pages, each 

 page bearing three columns of close print, and each column 



