But the centre of the Garden for reference and for detailed study is now the herbarium and library, housed in the large building near to the entrance from Kew Green. To those familiar with that magnificent mine of accumulated learning as it now stands, it may be a surprise to hear that it has grown in the course of less than 60 years out of the private collections of Sir William Hooker, and of his friend Bentham. The story of it may be gathered from the sketch of the Life and Labours of the First Director, published by Sir Joseph Hooker in the _Annals of Botany_ in 1903, a work to which I have been largely indebted for the materials for this lecture. The Hookerian herbarium and library were already extensive before it was removed from Glasgow. When the new Director of Kew took up his appointment, neither books nor a herbarium were provided for him: but he was well equipped with those of his own. They were at first lodged in his private house, till in 1853 he moved into the official residence. But the latter did not afford the accommodation for them which the Government had guaranteed. They were therefore placed in a building adjacent to the Botanic Garden. It was further agreed, on condition that the herbarium and library should be accessible to botanists, that he should be provided with a scientific herbarium Curator. Four years afterwards the Royal Gardens came into possession, by gift, of the very extensive library and herbarium of G. Bentham, Esq., which was second only to Hooker's own in extent, methodical arrangement, and nomenclature; and it was placed in the same building. The two collections in considerable degree overlapped, being derived from the same sources. But one great difference between them was that Bentham confined his herbarium to flowering plants, while Hooker's rapidly grew to be the richest in the world in both flowering and flowerless plants. Finally after his death it was acquired by purchase for the State in 1866, together with about 1000 volumes from his library, and a unique collection of botanical drawings, maps, MSS., portraits of botanists, and letters from botanical correspondents, which amounted to about 27,000. These were the prime foundations of the great herbarium and library now at Kew. Great additions have since been made by purchase and by gift, and the building has been repeatedly extended to receive the growing mass of material. But for all time the character and individuality of the collections will remain stamped by the personality of those two great benefactors, Bentham and the first Hooker.