The Class Urediniomycetes is a group of fungi within the phylum Basidiomycota, commonly known as rust fungi. They are primarily plant parasites, causing rust diseases on a wide range of crops and wild plants. Urediniomycetes have complex life cycles, often involving multiple spore stages and sometimes alternating between two different host species. These fungi are economically important due to the damage they cause to agriculture, but they also play roles in ecosystems by influencing plant population dynamics.