Basidiomycetes, a series of the higher fungi. They live on dead organic matter, and are made up of felted hyphal threads. No sexual process is known, and it has apparently been suppressed. They bear spores, known as basidiospores, generally four together, at the apex of cells called basidia. These basidia form part of a layer known as the hymenium, which is either on the surface, as in the order Hymenomycetes, which includes the mushrooms, or lining the interior, as in the Gasteromycetes, the puff-balls. The gelatinous Tremellini form a third order in this series.