This is the last volume of the late Professor Buller's monumental work on Fungi. Before his death in 1943, Dr. Buller had completed the manuscript; the final preparation for press has been made by Dr. G.R. Bisby of the Imperial Mycological Institute, Kew. Publication of the volume has been sponsored by the Royal Society of Canada, and the work of proofreading undertaken by Dr. W.E. Hanna, Dr. J.H. Craigie, and Dr. F.L. Drayton; the index has been prepared under Dr. Hanna's supervision. A foreword has been contributed by Dr. Joseph A. Pearce, President of the Royal Society.