Fungal Glossary

Acremonium is a fungus commonly found in soil, decaying vegetation, and damp building materials. Indoors, it may colonize materials exposed to prolonged moisture, including drywall and insulation. Certain species are associated with allergic responses and rare opportunistic infections.

 Alternaria is a widespread outdoor fungus associated with vegetation, soil, and decaying organic material. Its spores frequently enter buildings through outdoor air. Alternaria is a recognized respiratory allergen, with airborne concentrations influenced by seasonal and meteorological conditions. Indoor growth may occur on damp surfaces.

Arthrinium is primarily associated with soil, grasses, and decaying plant material. It is generally encountered indoors through outdoor air or contaminated organic debris. Its health significance is not well established, although some species have been associated with allergic responses.

 Ascospores are reproductive spores produced by fungi belonging to the Ascomycota. They are commonly found in outdoor air, particularly in association with vegetation and decomposing organic matter. Some ascospore-producing fungi can also colonize damp building materials. Many ascospores cannot be identified to genus through routine spore trap analysis. Health effects depend on the fungal species involved.

Aspergillus and Penicillium are widespread fungi found in indoor and outdoor environments. Their spores are commonly grouped during nonviable spore trap analysis because of similar microscopic characteristics. Certain species readily colonize moisture-damaged building materials. Some species are associated with allergic responses, opportunistic infections, or mycotoxin production. Identification to genus or species generally requires additional analytical methods.

 Aureobasidium is a yeast-like fungus commonly associated with moist surfaces, including window frames, bathrooms, painted surfaces, and areas with condensation. It is also found outdoors on vegetation. Exposure may contribute to allergic reactions in sensitive individuals.

 Basidiospores are reproductive spores produced by fungi such as mushrooms, puffballs, and wood-decaying fungi. They are abundant in outdoor environments, particularly during humid conditions. Their presence indoors commonly reflects outdoor air infiltration, although some basidiomycetes can grow on damp or decaying wood.

Bipolaris and Drechslera are fungi commonly associated with grasses, soil, and plant material. They may enter indoor environments through outdoor air or occur in damp areas. Some species are recognized allergens, and rare opportunistic infections have been reported.

Botrytis, commonly called gray mold, is frequently found on plants, flowers, fruits, and decaying vegetation. Its spores may enter buildings from outdoor sources or indoor plants. Exposure can contribute to allergic reactions or respiratory irritation in susceptible individuals.

Cercospora is primarily a plant-associated fungus commonly found on leaves and agricultural vegetation. Its spores may occasionally be detected in indoor air due to outdoor infiltration. It is not commonly associated with indoor building-material growth, and its health significance is generally limited.

Chaetomium is strongly associated with prolonged moisture exposure and deterioration of cellulose-containing building materials, including drywall paper, wood, and insulation backing. Its spores develop within enclosed fruiting structures called perithecia. Consequently, significant fungal growth may be present on a material without correspondingly elevated airborne spore concentrations. Certain species can produce mycotoxins, although routine microscopic analysis does not establish toxin production.

Cladosporium is among the most prevalent fungal genera in outdoor air and is routinely detected indoors. It occurs on vegetation, wood, fabrics, and damp surfaces. Indoor concentrations should be evaluated in relation to outdoor reference samples and the overall fungal profile. Cladosporium is a recognized allergen and may aggravate respiratory symptoms in susceptible individuals.

Curvularia is commonly associated with soil, grasses, and decaying vegetation, particularly in warm and humid environments. Its spores may enter buildings through outdoor air or occur on damp organic materials. Certain species are associated with allergic responses and rare opportunistic infections.

 Epicoccum is a widespread outdoor fungus commonly associated with soil, plants, and decaying organic matter. Its spores frequently enter buildings through ventilation and outdoor air. Epicoccum may contribute to allergic reactions in sensitive individuals.

Fusarium includes numerous species associated with soil, vegetation, and moisture-affected environments. Certain species can colonize persistently damp building materials and humidification systems, while others are important plant pathogens. Some species can produce mycotoxins or cause opportunistic infections. Routine spore identification does not establish toxin production or species-specific health risks.

Ganoderma is a genus of wood-decaying basidiomycete fungi commonly associated with trees, logs, and deteriorating wood. Its spores may occur in substantial concentrations in outdoor air and enter buildings through ventilation. Detection alone does not establish indoor fungal growth. Ganoderma spores may contribute to allergic responses.

Memnoniella is associated with chronically damp cellulose-containing materials, including drywall paper and other water-damaged building products. It shares environmental characteristics with Stachybotrys. Its detection may support further investigation of concealed moisture damage, particularly when accompanied by other moisture-associated fungal structures.

Myxomycetes, commonly called slime molds, are organisms typically associated with damp outdoor environments, decaying vegetation, and forest debris. Although their spores may resemble fungal spores during microscopic analysis, they are not true fungi. Their presence indoors generally reflects outdoor air infiltration, and their direct health significance is not well established.

Nigrospora is commonly associated with plants, soil, and decaying vegetation. It produces distinctive dark, nearly spherical spores that may be identified during microscopic examination. Indoor detection generally reflects outdoor air infiltration. Some species have been associated with allergic responses.

Oidium refers to powdery mildew fungi commonly associated with living plants. These fungi develop on plant surfaces and produce spores that may be detected in air samples. They are not typically associated with growth on conventional building materials, and their health significance is generally limited.

Pithomyces is commonly found in soil, leaf litter, and decomposing organic material. Its spores may enter indoor environments through outdoor air or contaminated debris. Certain species produce secondary metabolites, although microscopic detection does not establish toxin production or exposure.

Polytrinchium is an uncommon fungus primarily associated with outdoor vegetation and organic debris. Its spores may occasionally be detected indoors through outdoor air infiltration. Information regarding its indoor growth characteristics and potential health effects is limited.

Rusts and smuts are groups of plant-associated fungi commonly found on grasses, crops, and other vegetation. Their spores are dispersed through outdoor air and may enter buildings through ventilation. They are generally not associated with growth on indoor building materials. Some airborne spores may contribute to allergic responses.

Spegazzinia is primarily associated with soil, leaf litter, and decaying vegetation. Its distinctive spores may be detected in outdoor air and occasionally indoors through infiltration. Indoor growth is uncommon, and information regarding specific health effects is limited.

Stachybotrys is associated with prolonged saturation of cellulose-rich building materials, particularly drywall paper and other water-damaged products. Its spores are often produced in moist, cohesive masses and may be less readily aerosolized than spores of some other indoor fungi. Consequently, low airborne concentrations do not necessarily exclude significant growth on affected materials. Certain species can produce mycotoxins, but microscopic identification does not establish toxin production or exposure.

Stemphylium is commonly associated with plants, soil, and decaying vegetation. Its spores may enter buildings through outdoor air and are occasionally detected in moisture-affected environments. Some species are associated with allergic responses.

Tetraploa is an outdoor fungus commonly associated with grasses, soil, and decomposing plant material. Its spores often possess distinctive elongated appendages that aid microscopic recognition. Indoor detection generally reflects outdoor air infiltration rather than growth on building materials. Information regarding health effects is limited.

Trichocladium is commonly associated with soil, wood, and decomposing organic matter. Its spores may occasionally be detected indoors through outdoor infiltration or moisture-affected materials. Information regarding its specific health effects is limited.

Trichoderma is commonly associated with soil, decomposing vegetation, and moisture-damaged building materials. Certain species can colonize damp drywall, wood, and carpeting. Some species exhibit antagonistic activity against other fungi through competition, enzyme production, and secondary metabolites. Exposure may contribute to allergic responses, while opportunistic infections are rare.

Ulocladium is associated with damp building materials and other moisture-affected substrates, including drywall and wallpaper. Its detection, particularly alongside other moisture-associated fungal types, may support an investigation into water intrusion or persistent elevated humidity. Some species are associated with allergic responses.

Zygomycetes are a group of rapidly growing fungi commonly found in outdoor environments, particularly in soil, decaying vegetation, and organic debris. Their spores may enter buildings through normal outdoor air infiltration. They are widespread in nature and play an important role in the decomposition of organic matter.

General Fungal Information

The information provided is intended for general educational reference. Fungal spores occur naturally in indoor and outdoor environments. Their presence does not necessarily indicate active indoor fungal growth. Potential health effects vary according to the organism, exposure conditions, and individual susceptibility. Routine microscopic analysis does not determine mycotoxin concentrations, individual exposure, or health risk.

Any of a group of spore-producing organisms feeding on organic matter, including molds, yeast, mushrooms, and toadstools. 

A mold is a fungus that grows in the form of multicellular filaments called hyphae.

There is no single type of mold called “black mold”. Many molds are black. When people use the term, they may be referring to a type called Stachybotrys. However, not all molds that appear black are Stachybotrys.   

A general reference to certain types of mold that produce metabolic byproducts. These products are called mycotoxins. 

A toxic secondary metabolite produced by fungi. The adverse health effects of mycotoxins range from acute poisoning to long-term effects such as immune deficiency and cancer. The term 'mycotoxin' is usually reserved for, but not limited to the toxic chemical products produced by fungi that readily colonize crops. 

Fungal spores are microscopic biological particles that allow fungi to be reproduced, serving a similar purpose to that of seeds in the plant world. 

Conidia are a type of asexual spores (nonmotile) in fungi while a spore is a reproductive structure of fungi and some other organisms, containing one or more cells. 

(pl., hyphae) filamentous thread of fungal mycelium

Body of a fungus, most of which is underground or hidden within wood

An organism that obtains its nutrients from dead organic material.

A variety of compounds formed in the metabolism of fungi and bacteria. They are responsible for the musty odor you smell during the decay off-gassing from biological growth which includes molds, bacteria, and biofilm.