Chaetomium ascospores

Chaetomium ascospores are found in both outdoor and indoor air samples. In the natural environment, Chaetomium is a saprobe found in the soil and on decaying plant material. Indoors this genus readily grows on moist cellulose-based substrates such as drywall and ceiling tiles. Currently, this is the only ascospore genus with commercial allergy extracts for skin testing and treatment. The spores are brown and lemon-shaped with a germ pore (two in some species). They range in size from 8 -12 µm in length and 5-7 µm in width.