In memoriam Rudolf Arnold Maas Geesteranus Den Haag, 20 january 1911-Oegstgeest, 18 may 2003

On 18 May 2003 Rudolf Maas Geesteranus died peacefully at the age of 92. With him the mycological world has lost a remarkable and versatile personality, who worked on the taxonomy of fungi for almost 60 years producing papers and books on a wide range of topics, including both asco- and basidiomycetes. The bibliographical notes and publication list printed in this journal on his retirement from active service at the Rijksherbarium in 1976, and on his eightieth birthday in 1991 (Bas, Persoonia 8 (1976) 335-343, and Persoonia 14 (1992) 353-356) reflect the extent of his professional interests and output during his long career. After 1991 Maas Geesteranus went on tirelessly, producing another set of papers on the genus Mycena, which was his main interest in his last years of mycological activities. Milestones in this period were the two volumes of the Mycenas of the Northern Hemisphere (1992), a compilation of his vast knowledge of the genus, and a monograph of the Mycenas occurring in the state of Parana, Brazil, produced in close cooperation with André de Meijer (1997). Although Maas Geesteranus retired from active mycology a few years ago, he was well and active until his death, still very much engaged with his hobbies, such as the study of minerals, butterflies, and painting. Rudolf Maas Geesteranus will be remembered not only as an outstanding mycologist, but above all as a kind and helpful man, who advised and stimulated several generations of mycologists, both professional and amateur. For this we are very grateful. Our thoughts are with Martha, his wife, and his children and grandchildren, who will miss him dearly.