Variations in cultivation characteristics of Thai and Japanese stocks of oyster mushroom and their F₁ hybrids were studied. Crossing experiments revealed that mating factors of the two stocks were compatible (A≠, B≠). In cultivation at 22°C, Thai stock flushed twice or more, and Japanese stock once or not at all. However at 15°C, Japanese stock normally flushed twice. While some F₁ hybrids flushed once or not at all (F₁-L), and others flushed twice or more (F₁-H). The hybrids graded as F₁-H were capable of fruiting well in a wider range of temperature than those graded as F₁-L. In principal component analysis of data including days required for fruiting, fruiting productivity (yield), pileus color and shape, each stocks was compared on a Z-score diagram of their first and second principal components. The stocks of F₁-H and F₁-L hybrids formed each clusters on the diagram, and the Thai and Japanese parental stocks were located near or within the clusters of F₁-H and that of F₁-L, respectively. In fruiting characteristics, most members of both the clusters lay in the same area at 22°C, but at 15°C, they segregated in distinct areas. Some characteristics appeared to be linked and inherited. Introduction of Thai germplasm into Japanese stocks will be effective to improve their cultivation traits.

　The modes of hyphal interactions were examined in and around lateral roots of Cucumis sativus 'Suyo' seedlings (cucumber) pre-treated with the mycoparasitic Pythium oligandrum (parasite), and then inoculated with the phytopathogenic P. ultimum var. ultimum (host) in soil. Cucumber seedlings completely damped-off and died within 2 days when inoculated with the host alone. When inoculated only with the parasite no seedlings were killed, and the seedling growth was delayed and restored. Furthermore, the growth of the seedlings was delayed in early stages when pre-treated with the parasite before inoculating the host, and about 50% of the seedlings remained standing. Host hyphae vigorously penetrated into the roots. Parasite hyphae were, however, found on the root surface. Parasite mycelium repeatedly approached, trapped, and penetrated the host mycelium. Protoplasm of the host mycelium granulated as it made contact with the parasite. Host mycelium was septated and disappeared as it was trapped and penetrated. In the presence of the parasite, protoplasm of the host mycelium degenerated and produced abundant oospores in the early stages. Abundant parasite hyphae but fewer oospores were observed in the presence of the host.

　The amateur's role in the history of mycology will be traced from its early roots deeply based in the collection of fungi for food to the amateur's present day activities. Attention will be drawn to the most important key amateur figures studying fungi solely or as a wider part of natural history in the eighteenth and nineteenth centuries, and the early part of the present century. How their work influenced the development of mycology will be demonstrated. It is often forgotten that the authorities attached to fungal names, including those we use in mycology on a daily basis, often belong to amateurs. The true professions of these amateurs, the net-work of correspondents they developed, etc. will be revealed and discussed in the context of an overall understanding of fungi as organisms. In addition the formation of mycological societies, and how they have become a focus of amateur activity and a source of accurate and disciplined information valuable to professional scientists will be plotted. The kind of work undertaken by amateurs I refer to will be demonstrated by documenting the activities of the British Mycological Society which celebrated its centenary in 1996. The continuing work of this band of workers and their counterparts throughout the world in the closing years of the millennium will be described. It is argued that they are nationally important and necessary resources, despite many governments or their advisers, especially the most influential ones, being under the delusion that systematics is not cutting edge science. It is also emphasized that amateurs will have an even more important role to play in the future as custodians of knowledge―until hopefully opinions change.