The list below provides basic information on the most common fungi isolated during air sampling outdoors or indoors and the links provide images of these spores.
Alternaria - common genus of asexual ascomycetes especially in outdoor environments; airborne Alternaria conidia are often the second most common fungal spore genus in temperate climates around the world. It is a common saprobe, leaf surface organism, and plant pathogens. Alternaria spores are highly allergenic. It can grow on a number of indoor substrates, but it is usually not found at high levels indoors.
Ascospores - spores produced by the sexual stage of ascomycetes. Usually found in outdoor air samples during wet weather and may be introduced indoors. Ascospores are suspected allergens but have not been well studied. See Chaetomium below.
Aspergillus - common fungal genus of asexual ascomycetes with airborne conidia. In nature this genus typically occurs in the soil, and is especially common in moisture damaged indoor environments. Various species of Aspergillus have been implicated in human infections and other species are plant pathogens. Some Aspergillus species are known to produce mycotoxins under certain environmental conditions. Aspergillus conidia are known to be allergenic. Aspergillus and Penicillium are closely related fungi with similar conidia, and culturing is needed to identify the genus. On spore trap samples these are usually identified as Penicillium/Aspergillus-type spores.
Basidiospores - sexual spores produced by mushrooms, bracket fungi, puffballs and other basidiomycetes. Common in the outdoor environment and introduced indoors with outdoor air. Indoor sources of basidiospores are from dry rot. Many basidiospores are allergenic based on clinic studies, but no extracts are currently available for testing and treatment.
Chaetomium - ascospores of this genus can be 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.
Cladosporium - common fungal genus of asexual ascomycetes occurring both indoors and outdoors. Cladosporium species have a worldwide distribution, and on a yearly basis Cladosporium conidia are the most abundant outdoor spore type in temperate climates. The fungus normally exists as a saprophyte or weak plant pathogen, and the spores are known to be allergenic.
Curvularia - an asexual ascomycete genus whose conidia are present in outdoor air. In the natural environment, Curvularia species occur as saprobes and plant pathogens. Curvularia can be a cause of allergic fungal sinusitis, and the conidia are allergenic.
Drechslera/Bipolaris-type - conidia are similar in several asexual ascomycetes genera including Drechslera, Bipolaris, Helminthosporium, and Exserohilum. These fungi are either plant pathogens or saprobes in the natural environment, and their conidia are airborne. They are known to be allergenic and can also cause fungal sinusitis. Because these genera have similar conidia, they are usually identified as Drechslera/Bipolaris-type spores in air sample analysis.
Epicoccum - an asexual ascomycete genus that is a common saprobe both indoors and outdoors. Epicoccum can grow on many substrates. At times the outdoor concentrations are high in agricultural areas. Known to be allergenic and possibly cross react with Alternaria.
Fusarium - a fungal genus of asexual ascomycetes that is a soil saprobe and an important plant pathogen. It normally is found in the soil but can be introduced indoors. Indoors it is often found in the bathroom or other areas with moisture. Some species of Fusarium produce mycotoxins.
Myxomycete spores - spores produced by slime molds (fungal-llike organisms in the phylum Myxomycota) and seen in outdoor air samples. These spores are occassionaly seen indoors as well.
Penicillium - common asexual ascomycete genus with airborne conidia. In nature Penicillium typically occurs in the soil, and is especially common in moisture damaged indoor environments. Also commonly found on moldy food. Penicillium conidia are known to be allergenic. Aspergillus and Penicillium are closely related fungi with similar conidia, and culturing is needed to identify the genus. On spore trap samples these are usually identified as Penicillium/Aspergillus-type spores.
Pithomyces - conidia of this asexual ascomycete generally occur in low numbers in Tulsa outdoor air samples, are seldom found as an indoor contaminant. The genus is primarily a saprobe on decaying plant material. The spores are possibly allergenic but have not been well studied.
Rhizopus - common saprobe in the Mucoromycota that grows on a variety of substrates, especially spoiled food. Often isolated during culture-based air sampling. Spores are allergenic
Rust spores - spores produced by rust fungi, which are common plant pathogens that can cause severe disease on many plant species. Two types of rust spores, uredospores (urediniospores) and teliospores are commonly seen on air samples.
Smut spores - teliospores produced by smut fungi, which are common plant pathogens that are especially prominent on cereals and other grasses. Smut spores are frequently seen in the outdoor atmosphere and can be introduced indoors with outdoor air. Spores are allergenic but not well studied.
Stachybotrys - a soil fungus in the natural environment. Commonly found indoors on wet cellulose-based materials, such as drywall, ceiling tiles, jute, wicker, straw baskets, and paper materials. Some consider it to be allergenic although little is known. Some strains of this genus produce mycotoxins.