Smut fungi are common plant pathogens that are especially prominent on cereals and other grasses. Smut teliospores are frequently seen in outdoor air samples in Tulsa, and these spores can be introduced indoors with outdoor air. Spores are allergenic but not well studied. See Smut fungi for additional information.
The smut teliospores are typically globose to sub-globose and single-celled ranging from 5 to 15 µm in diameter. The cell wall of teliospores is frequently spiny, warty, or reticulate. In some smut species the teliospore wall is unevenly thickened with thin and thicker areas. In the genus Urocystis, the teliospore consists of a central fertile cell, which is surrounded by a group of flattened sterile cells. This multicellular teliospore is referred to as a spore ball and is shown in in lower right photo below.