WHEN the author died in 1954, he had nearly completed his work and only a few trivial emendations and additions have been made. All the descriptions were complete with the exception of the section Appendiculati which has been prepared from his account of the series and subseries. In the analytical key there was no method of arriving at the sections, subsections, series and subseries. As it seemed undesirable that the text should have to be consulted to arrive at the appropriate group, the group descriptions have been extracted from the text and incorporated into the key. Under the nomenclature only dates had been quoted, but it seemed desirable to have full references. This has been done with the exception of the group headings. No authority or reference for the group headings, many of which are new or have new status, had been given by the author, and it has only proved practicable to give basonym authorities. All new names and combinations have been published separately in a paper in Watsonia. All the type material from Watson's herbarium has been deposited at the British Museum (Nat. Hist.).

It is believed that the author would have wished to thank Miss Ruth M. Ball and Mr A. W. Darnell for drawing the illustrations; the authorities of the British Museum (Nat. Hist.) and the South London Botanical Institute for the use of specimens and books; and the many fellow botanists for help received during his life-long study of the genus Rubus, which has resulted in this, his most considerable work.