Basidiomycetous fungus refers to a large group of fungi that produce spores on basidia, which are specialized club-shaped structures. This group includes some of the world's most important fungal pathogens, such as the rusts and smuts, which can cause significant damage to crops. There are several synonyms for basidiomycetous fungus, such as club fungi, jelly fungi, and bracket fungi, which refer to their characteristic shapes and growth patterns. Another synonym is agaric, which refers to a subgroup of basidiomycetes that have a cap and stem with gills on the underside, such as the common button mushroom. Other synonyms include puffballs, stinkhorns, and bird's nest fungi, which are all basidiomycetes with unique fruiting bodies and reproductive strategies.