Abstract
Agaricus subrufescens is an edible and medicinal mushroom of Agaricaceae, Agaricales originally described from North America. It has increasingly been used as a health food and alternative medicine and is also used in cosmetics. Agaricus subrufescens has been shown to exhibit many pharmaceutical traits such as anti-cancer, anti-microbial and immunomodulatory properties and is rich in bioactive compounds, especially beta-glucans. Recently, four specimens of Agaricus subrufescens were collected from northern Thailand and are the first records of this taxon for Thailand and surrounding regions. The data from macro-and microscopic features are consistent with the characteristics of the species. The molecular data indicates the Thai collections cluster in A. subrufescens sensu lato. The species is reported here because of the significance of finding this very important taxon in Thailand which has both commercial and biotechnological potential.