Alternaria
A genus of fungi that is extremely widespread and ubiquitous. It is commonly found in outdoor samples and may be isolated from samples of soil, seeds, and plants. Alternaria is also often found in carpets, textiles, window frames, and on horizontal surfaces in building interiors. It is both a plant pathogen and human pathogen. Alternaria produces large spores, suggesting that the spores from this fungus are deposited in the nose, mouth, and upper respiratory tract.

Ascospores
A large group of spores that are very ubiquitous in nature. They are frequently found in the air after a rain. Most ascospores are plant pathogens; a small portion have been known to cause infection in humans.

Basidiospores
A large group of spores that are very ubiquitous in nature. They are released from mushrooms, shelf fungi, puffballs, and a variety of other macro fungi. Basidiospores may be allergenic to those with seasonal allergies.

Cladosporium
One of the most commonly identified outdoor fungi. It is often found indoors in numbers less than outdoors. Cladosporium is also found on decaying plants and food, straw, paint, and textiles. It is generally regarded to be allergenic and can be a cause of extrinsic asthma

Epicoccum nigrum
Epicoccum nigrum (also known as Epicoccum purpurascens) is the only species in the genus Epicoccum. It is very commonly isolated from plants, air, animals, foodstuffs, and textiles.

Ganoderma
A type of basidiospore from a genus of mushrooms known as shelf mushrooms or bracket fungi, which grow on wood. These spores may be allergenic to those with seasonal allergies.

Hyphal Fragment
A tubular filament which is the vegetative, nutrient-absorbing portion of the fungus.

Mitospores
A large group of morphologically-similar fungi which includes Alternaria, Stemphylium, Pithomyces, and Ulocladium. If hyphal fragments are not attached to the spores, the specific type of mitospore cannot be differentiated and is classified under this grouping. Because mitospores are large spores, they are more easily deposited in the nose, mouth, and upper respiratory tract, allowing them to be potentially very allergenic. Alternaria, Stemphylium, Pithomyces, and Ulocladium are all commonly found on plants, textiles, paper, and in soil. In building interiors, they are commonly isolated from horizontal surfaces (e.g. window sills, attic rafters). Alternaria is both a plant pathogen and human pathogen and is associated with asthma, hypersensitivity pneumonitis, sinusitis, deratomycosis, onychomycosis, subcutaneous phaeohyphomycosis, and invasive infection. Stemphylium is not a known human pathogen. Pithomyces is not a known human pathogen, but has been known to cause facial eczema on ruminants (e.g. cattle, goats, sheep).

Pen/Asp group
The spores of the genera Penicillium, Aspergillus, and Trichoderma are quite similar when viewed under a microscope and are grouped together under the heading Pen/Asp. Penicillium species are among the most common fungi found in indoor environments, particularly basements. Certain species may cause infections of the eye, external ear, respiratory system, and urinary tract. Some species of Aspergillus are parasitic on insects, plants, and animals including humans. All Aspergillus species are allergenic. Various species can cause extrinsic asthma, pulmonary emphysema, opportunistic infections of the ears and eyes, and severe pulmonary infections. Some species of Penicillium, Aspergillus, and Trichoderma produce mycotoxins
which may be associated with diseases in humans and animals. Several toxins are considered potential human carcinogens. The genus Trichoderma has been reported to cause infections in immunocompromised individuals, patients undergoing dialysis, and individuals with chronic kidney failure or chronic lung disease.

Pollen
Pollen are coarse to fine particles/grains produced by various trees, weeds, and grasses. For individuals with seasonal allergies, pollen is often the causative agent.

Polythrincium
A fungus commonly found outdoors, mainly on plant leaves. It is not a known human pathogen.

Smuts/Periconia/Myxomycetes
A group of plant pathogens with similar morphology. They are commonly found in the outdoor environment in soil and on wood, grasses, cereal crops, and flowering plants. Myxomycete spores are considered to cause Type 1 allergies (hay fever and asthma).