EEVIEW. 275
been pushed south by the advancing ice into' America as well as Asia, and had found congenial sites in the forest area of the east coast of America, but the ice-cap remaining long on the Rockies, had prevented these plants from settling there except in some favoured localities, while the desert region which developed in the middle of the continent prevented the eastern plants from re-invading the Rockies, which were eventually peopled largely from Mexico. With regard to Greenland, Hooker believed that the advance of the ice-cap there had pushed the plants into the sea, so that there could be no return for them, and nore-peopling from elsewhere, hence the paucity of the Greenland flora. He was inclined to accept Buffon and Saporta's view that vegetable life may have begun at one of the poles, because these would be the first regions to become cool enough to support life, and the balance of evidence seemed to him to point to the north pole, because distribution has apparently flowed in general from north to south, as already noted with regard to India and Australia. Scandinavian types are very widely distributed ; and old types, such as cycads and Proteaceae have perhaps reached the southern hemisphere in quite recent geological times, while becoming almost extinct in the north.
After this journey in America, Hooker had botanized in all the continents of the world, as well as on many oceanic islands. Yet these expeditions formed the smallest part of his life-work : for the greatest part he was at Kew, where he worked up not only his own collections but those of others. He published a Flora of-the Cameroons, wrote on the Galapagos, plants, and on the distribution of Arctic Plants. The immense herbarium was gradually brought into order and constantly added to, the gardens were improved, and new buildings added ; he was always ready to make observations and experiments for Darwin on the structure cf orchids, the habits of carnivorous plants, etc., and he took a great interest in the econo- mic botany of the Empire. In the 70's there was a great demand for eucalyptus trees to combat malaria, and many were supplied from Kew : to Hooker was due the importation of rubber, of which he foresaw the importance, into Ceylon, Fiji, Australia, Java, and Zanzibar ; Liberian coffee first grown at Kew became a flourishing crop in the East and West Indies; chocolate was introduced into Ceylon, cinchona established in India, and various fodder grasses were taken to new centres. The cigar industry in Jamaica was due to Hooker, and together with other crops, such as cinchona and fruits, rescued the island from bankruptcy when the sugar industry failed. Hooker's advice was that small cheap botanical gardens, for economical plants only, should be started in all our colonies.
After being Sir Willian Hooker's assistant at Kew from 1855, Sir Joseph naturally stepped into his father's place when the latter died, and was Director of Kew from 1865 to 1885. On his retirement, a private letter from Lord Iddesleigh expressed the opinion that Kew would be to Joseph Hooker what St. Paul's was to Wren. Sir Joseph sent thanks in the name of his family, so as to include his father, to whom he was always loyal by devoted, and in a letter to a friend be acknowledges that "Kew is what my father and I have made it by our sole unaided efforts." His influence on botanical science was felt in many ways, especially as he was member of many scientific and learned societies, and President of the Royal Society. He retired only to work harder than ever at his plants, freed from the administrative and offiicial duties of his position at Kew.
Although he was twice married, none of Hooker's children became botanists, but his daughter's husband, William Thistleton-Dyer. who had been his private secretary, succeeded hira as Director at Kew,
