Mold Glossary

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Learning about mold types, characteristics, symptoms, and health effects can help you determine if you need to seek professional mold cleaning and mold removal services.

If you do require further assistance or a professional assessment, give us a call anytime day or night at (916) 244-3961.

Molds are organized into three main classifications based on their subsequent human responses:

  1. Allergenic Molds
    Allergenic molds are not typically considered life-threatening and are most likely to affect those who are already allergic or asthmatic. The human system responses to allergenic molds tend to be relatively mild, typically producing sore or scratchy throats, eye and nose irritations and rashes.
  2. Pathogenic Molds
    Pathogenic molds tend to be associated with some type of infection. Those who suffer from a more suppressed immune system are mostly likely to experience more sever heath effects from these molds. Healthy people can usually naturally resist infection. In rare cases, high exposure may cause hypersensitivity pneumonitis (an acute response to exposure to an organism).
  3. Toxigenic Molds
    Of the three, toxigenic molds can cause the most serious health effects. Mycotoxins have toxic effects ranging from short-term irritation to immunosuppression and possibly cancer. Therefore, when toxigenic molds are found, immediate evaluation is recommended.


A genus of fungi in the family called Mucoraceae. Considered allergenic and can cause mucorosis in persons with low immunity. The infected sites are mostly lungs, nose, brain, eyesight and skin. Sometimes there may be many infected places.


A genus of fungi that tends to be slow growing, but potentially harmful if ingested. Acremonium contains approximately 100 species. Colonies are often compact and moist initially. After time, they become powdery and suede-like, sometimes white or grey in color. Can be allergenic if ingested.


Alternaria is a genus of ascomycete fungi. Alternaria species are known as major plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead to asthma. Alternaria is mostly found in indoor areas like dust, rugs, clothing materials, foodstuffs and on flat surfaces e.g. window sills. It is usually isolated away from substrates like sewage, monuments, leather, computer disks, optical instruments, cosmetics and even jet fuel. Outside, it could be found on dead matter or debris, and may aid the rotting of agricultural products in the soil or air — one reason why it is found everywhere. Alternaria conidium is carried by wind easily, and has full air concentrations during summer and early fall seasons.


An oval-shaped single cell, fungal spore which is difficult to identify. These types of mold spores generally include Penicillium, Aspergillus, Trichoderma and others. For instance, Penicillium can easily be identified during sampling by using culturing methods.


A spore borne in a special cell called an ascus. The minute black dots on rotting wood and leaves or the little cups on lichens are examples of ascomycetes. Spores of this type are reported to be allergenic.

Aspergillus candidus

Typically grows in grains, warm soils and in areas where there is secondary vegetation decay. This type of mold has been correlated to respiratory problems in humans during a recent house inspection. It could produce the toxin patulin which may be a cause of diseases in humans or animals.

Aspergillus clavatus

This species is occasionally classified as pathogenic. Typically found in animal manure or plain soil, it can produce the toxin patulin which may be a cause of diseases in humans or animals.

Aspergillus flavus

Some of its strains have been known to produce mycotoxins, particularly aflatoxins, which are classified as animal carcinogens. These toxins are poisons to humans if ingested. If inhaled, it could also result in occupational disease. Generally, Aspergillus flavus can be found in foods, warm soil, and dairy products. Many times, its presence is sound in water-damaged rugs.

Aspergillus fumigatus

Classified as a human pathogen, Aspergillus fumigates is an organism causing both allergic and invasive aspergillosis (the invasive type usually affects people who are lightly immune). It is mostly thrives in outdoor areas or in cereal grains, warm or cool soils, and in compost material.

Aspergillus glaucus

It is identified as an outdoor fungus that is usually found during winter periods and grows in low moisture levels (e.g., grains, wool, sugary products and meat). It is said to be allergenic, but sometimes falls under the pathogenic category.

Aspergillus nidulans

It has been known to produce mycotoxin sterigmatocystin. This toxin type is known to damage the liver and kidney in laboratory animals. It is typically found in light to warm soils and on slowly rotting plants. Overall, this fungus is classified as pathogenic and is often linked to lung aspergillosis and/or disseminated aspergillosis.

Aspergillus niger

Described as a less common causative agent of aspergillosis with a musty odor. This can be found across a range of locations like soils, textiles, grains, vegetables and fruits. It has the potential to cause pulmonary and skin infections to a large degree and fungal-induced ear infections like otomycosis.

Aspergillus ochraceus

Aw 0.77; Conidia sizes of 2.5 to 3 microns is commonly found inside the soil, grains and salted food content. This type is not normally linked to decomposing vegetation and could yield kidney toxin ochratoxin A capable of further producing ochratoxicosis in human beings. This is generally called Balkan nephropathy. This toxin is manufactured at optimum growth conditions of around 25 deg. Celsius and high atmospheric moisture. The ochratoxin could also be a product of Aspergillus sp. and Penicillium sp. Other types of toxins that are products of this fungus are penicillic acid, viomellein and xanthomegnin. These are all toxins related to the kidney and liver.

Aspergillus parasiticus

Some of its strains are able to produce groups of mycotoxins within the larger aflatoxin group. The group is known as animal carcinogens even though there is light evidence to indicate that the toxin type is a human carcinogen. If ingested, the toxin is poisonous to the human liver and experiments show that it is both mutagenic and teratogenic. The fungal toxin produced largely depends on the conditions of growth and on the substrate as well.

Aspergillus versicolor

Found mainly in cool climates, it is usually found indoor environments including dusty areas, foods such as dairy products and cotton. However, it is also known to grown in soils and hay. It typically considered an allergenic mold, but some strains have been known to produce several mcotoxina. If ingested, it can cause diarrhea, upset stomach and possible carcinogen which in turn affects the kidney and liver.


A genus of mold considered generally pathogenic. Many members of this genus have been linked with ear infections among humans. A lot of its species reproduce mycotoxins that could be linked to humans and animal diseases. The toxins produced depend on the types or strains of the species and also on the source of food for the fungus. Some toxins have been discovered as carcinogenic in species of animals while many toxins are seen as potential human carcinogens. They may cause allergic symptoms like sinusitis, bronchopulmonary aspergillosis, etc.


Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. Most basidiospores are forcibly discharged, and are thus considered ballistospores.


This is a type of fungus that has big spores which may be deposited inside the upper respiratory tract of humans. This type of fungus is capable of producing mycotoxin, discovered to produce kidney and liver damage through ingestion by lab animals.


Blastomyces is a fungal genus responsible for the medical condition blastomycosis. Considered a human pathogen, this type of fungus is mostly found inside soil samples and is primarily found in the Mid-West and Northern United States and Canada.


A genus of fungi in the Chaetomiaceae family. It is a dark-walled mold typically found in soil, air, and plant debris. Infections in humans can be avoided by proper hygiene habits. For instance, the Sohnian Kittah strain's presence can often be eliminated entirely with household products.

Cladosporium (Hormodendrum)

Species of Cladosporium are not human pathogens except in some cases of immuno-compromised patients. Cladosporium species have the ability to trigger allergic reactions to sensitive individuals. The outdoor concentration of this mold is reduced during winter but is usually high during summer. It is lesser indoors than outdoors and remains a common allergen. The outdoor members can mostly be found atop fiberglass surfaces and inside duct liners. Food sources for this type of fungus include a wide variety of plants. It grows on dead or woody plants, paint, straw, food, soil and textiles and yields more than 10 antigens. It is linked to extrinsic asthma i.e. type I, immediate-type hypersensitivity. Severe symptoms could be eye ulceration, skin lesions, onychomycosis or mycosis, finger & toenail infection, bronchiospasms. Chronic cases may cause pulmonary emphysema.

Cladosporium herbarum

A commonly known and detected mold type. Indoors, it is found in floor, carpet and mattress dust, damp acrylic painted walls, wallpaper, HVAC insulation, filters and fans. Cladosporium herbarum is frequently the most prominent mold in air-spora. It grows over a wide range of temperatures, and has frequently been reported causing spoilage of meat in cold storage.

Cladosporium sphaerospermum

This is a frequently encountered species of Cladosporium. It has been isolated from air, soil, acrylic painted walls, painted wood, wallpaper, carpet and mattress dust, HVAC fans, wet insulation in mechanical cooling units, foodstuffs, paint and textiles.

Cryptococcus neoformans

This is a fungal organism that is encapsulated and grows worldwide but mostly around places where pigeons roost, contaminated soil harboring decayed droppings of pigeons or chickens. It is widely known that this organism gains entry into the host’s body system through the respiratory ducts in form of basidiospores or dehydrated haploid yeast. It then spreads hematogenously to extrapulmonary tissues. Although the genus Cryptococcus contains more than 50 species, only C neoformans and Cryptococcus gattii are considered principal pathogens in humans.


It is a fungal genus classified as a member of the category called, “Dematiaceous Hyphomycetes,” and has the potential to cause phaeohyphomycosis. It tends to produce quickly in freshwater and terrestrial environs. Its colonies are sometimes colored black, dark brown, or greenish black.


Plant pathogen causing leaf spot, crown rot, and root rot of various turfgrass species. It sometimes causes eye infections in parts like the cornea.


Epioccum is a sooty mold that thrives in cool and moist weather conditions. It is a common allergen lodged in soil, grains, plants, textiles, wood and paper materials.


A genus of fungus causing superficial and cutaneous mycoses, including E. floccosum, a cause of ringworm, jock itch, athlete’s foot, and onychomycosis or tinea unguium, a fungal infection of the nail bed.


Abundant worldwide, fungi typically become noticeable when fruiting, either as mushrooms or molds. Fungus is neither a plant nor animal, but is rated as parasitic and saprophytic spores which produce organisms under their own taxonomic category. Around 100,000 species of fungi have been formally described by taxonomists. Fungi can take the form of mildew, molds, mildews, rusts, smuts, puffballs, mushrooms and yeasts.


Fusarium is a large genus of fungi widely found in soil and in association with plants. While most species are harmless saprobes, there are some species that produce mycotoxins in cereal crops. They can adversely affect human and animal health if ingested. The main toxins produced by these Fusarium species are fumonisins and trichothecenes. This has been linked to diarrhea, dermatitis, nausea, vomiting and prolonged internal bleeding. However, it is mostly reflected in infections of the skin, eye, and nails.


Geotrichum is a genus of fungi found in a variety of environs in soil, water, air, and sewage, as well as in plants, cereals, and dairy products; it is also commonly found in normal human flora and is secluded from sputum and feces. Geotrichum candidum species could cause geotrichosis which is a secondary infection linked to tuberculosis. Although a rare disease, it may cause skin, mouth, lung, bronchi and intestine lesions.


A mitosporic mold often encountered on decaying plant matter. There are no available reported effects upon human health in the indoor environment. Scientists have proven the interaction of Helicomyces roseus with nitrogen-fixing bacteria to be an essential component of an effective soil enriching system.


A fungus that has filamentous growth at 25 degrees C. and yeast growth at 37 degrees C. It is classified to be a human pathogen and may be contaminated through birds.

Hyaline mycelia

Mycelia are characterized by being transparent, translucent, and colorless. If no reproductive structures are present, it is extremely difficult to detect and identify Mycelia. Generally, this type of mold is associated with allergic symptoms.


Memnoniella echinata is a widespread strongly cellulolytic fungus. It has been extracted from cotton, canvas, hardboard and woollen fabrics. Memnoniella echinata is very similar to Stachybotrys but it produces spores in chains. It is common on very wet gypsum board. Recent mycotoxins experiments show that Memnoniella echinata may possess similar toxicity to some Stachybotrys chartarum. Both types may produce different simple trichothecenes amounts. The main difference the two fungi types have is the conidia of Memnoniella sp. which is in endless chains but combined slimy heads are represented for the Stachybotrys type. Therefore, it is recommended to seek professional mold removal and cleaning services in this instance.


Molds are classified as organisms with more than 20,000 species represented under the Fungi taxonomic kingdom. Common molds are Acremonium, Aspergillus, Cladosporium, Fusarium, Mucor, and Strachybotrys. Molds are produced through spores which continually float in the air. Once the spores of mold land indoors and find any damp area, they could start springing up; digesting all they grow on. Molds germinate on almost all organic substances, provided there is oxygen and moisture.


Mucor thrives in meat, leather, animal fur, and even dairy products and human hair. It’s a Zygomycetes type of fungus that can be allergenic and passed through the skin and respiratory system. This form of organism and similar types often grow quickly on many fungal environments. Although it is not harmful in most cases, it could cause mucorosis in lightly immune persons, affecting the brain, eye, lung, nose and skin.


Mycelium is the vegetative part of a fungus. Fungal colonies consisting of mycelia are found in soil and on or within many other substrates. It is an important food source for many soil invertebrates.


This is a fungus that falls under the "slime molds" category. Myxomycetes can be found indoors, but they commonly grow in forest zones on the surfaces of stumps, decaying logs and dead leaves. In favorable conditions like damp places, it indicates amoeba-like cells, usually surrounded by just a plasma membrane. They vary greatly in size and pattern. When dry, this species forms a sclerotium or resting body with the airborne but dry spores. It does not typically yield toxins, except it sometimes contributes to asthma and hay fever symptoms.


This mold type mostly grows in warm regions, and could be the cause of allergic reactions like asthma and hay fever. It usually thrives on soil or decaying plant matter but never found indoors.


The fungus is a plant pathogen which causes mildew in powdery form. It commonly grows on the stems of leaves and plant flowers. Presently, it is considered allergenic and its health effects are yet to be studied and it has not been found on non-living surfaces e.g. drywall or wood.


Classified as allergenic and typically found in dust and soil, less often than in air. It is usually associated with humidifier related and wood-trimmer's diseases or illnesses. Species of this genus are harbingers of pneumonia and may yield arsine gas. Paecilomyces are gold, green – gold, lilac or tan, but never blue or green.


Penicillium is a genus of ascomycetous fungi and holds great importance in the natural environment as well as food and drug production. It produces penicillin, a molecule that is used as an antibiotic, which kills or stops the growth of certain kinds of bacteria inside the body. The conidia are typically carried by air currents to new colonies. The conidia tend to be blue to blue-green, and the mold sometimes exudes a yellow pigment.


A small flask-shaped fruiting body found as part of some ascomycete fungi. It is the part of the fugus where certain types of spores are formed.


Peronospora is a genus of plant pathogens, belonging to the class of water molds. As a water mold, it is not classified as a true fungus. Instead, it is a plant pathogen example of species whose genus is the cause of downy mildews. Typically, they are found on stems, leaves, flowers, vegetables, and fruits. Health effects and toxicity are yet to be studied sufficiently to determine its characteristics.


Phaeohyphomycosis is a heterogeneous group of mycotic infections caused by dematiaceous fungi whose morphologic characteristics in tissue include hyphae, yeast-like cells, or a combination of these. Different types of its disease affect various parts of the human body e.g. the respiratory tract and skin. Invasion of this mold into the brain, eye, bone or subcutaneous tissue and this usually happens due to the trauma of the affected area.


It is classified as an air allgergen and is commonly found indoors. Phoma has been known to cause asthma and hay fever. It is a commonly associated with “shower curtain disease.” These shower surfaces are somehow integrated with the fungal organism. Human phoma infection usually affects people with low immunity. They are fungal infection of the cornea or mycotic keratitis, phaeohyphomycosis, etc.


Pithomyces can be found mostly in tropical regions, where it easily grows on soil, wood, dead plants and leaves, grasses, straw and livestock fodder. It has generally been linked to liver damage in animals, facial eczema in domestic animals. As for humans, it is classified as an allergen, with an infectious agent that compromises low immunity patients.


The fungus is described as an allergenic and occupational allergy. In poorly immuned persons, it has been known to cause mucorosis. Infections can turn up in multiple places.


Rhodotorula is a reddish colored type of yeast which thrives in moist or humid places like carpet materials, drain pans and cooling coils. In some locations, this type of yeast genus is very common and can be found in indoor areas. Based on positive skin tests, it is considered allergenic.

Rusts (and smuts)

A type of fungus most commonly associated with plants. In fungi taxonomy, smuts are very similar to rusts. The two groups produce wind-carrying, resistant teliospores which is the basis for how they are classified. Rusts are known to attack the vegetative part of plants, while smuts are mostly related to plants reproductive parts such as seeds. They are causes of asthma and hay fever.


It grows on various materials e.g. house dust and is linked to type III allergies. It tends to produce arsine gas as it grows on arsenic substrat, particularly on wallpaper surfaces with Paris green layers.


Identified as having yellow or colorless round, spiral, 1-shaped cells, which grow singly towards the short ends of its filaments. Some species of Mortierella, and the human pathogen Histoplasma capsulatum, have similar spores to Sepedonium.

Serpula lacrymans
Its acute symptoms are bronchiospasms & edema; chronic cases may cause pulmonary emphysema.


See rusts.


It is classified as a type of mitosporic fungus, labeled as "Hyphomycetes" or spores formed through asexual cell division. Currently, no information is available regarding health effects or toxicity. Allergenicity has not been studied. Spegazzinia spores may be seen in samples of air through their unique structure, and are capable of building a colony in 7 to 10 days. These colonies are comparably slow in growth, and are black and brownish black colored. This type of saprobe lives off of non-living or rotting organic materials and mostly grows in slightly warm to tropical places.


A spore is a reproductive structure that is adapted for dispersal. Spores can exist for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoans. Spores are 2 to 100 micrometers in microscopic size and come in different shapes. It could be distributed through water droplets, wind, humans or animals moving around. They may also be dispersed by the mold under normal moist or high humidity conditions.


This type of mitosporic fungus is part of the "Hyphomycetes" There is very little known about its toxicity or its allergenic property. It usually thrives on tree barks, wood or stems, and could survive in fresh water. Its microscopic features are quadriseptate spores, developed in enclosed membranes.


Stachybotrys is a genus of molds that is closely related to the genus Memnoniella. The majority of Stachybotrys species inhabit materials rich in cellulose. The genus has a widespread distribution, and contains about 50 species.[The most infamous species, S. chartarum is known as "black mold" or "toxic black mold," and is frequently associated with poor indoor air quality that arises after fungal growth on water-damaged building materials. It is known to produce trichothecene mycotoxins including satratoxins. Persons who have severe risks to Stachybotrys's toxins complained of flu or cold symptoms, diarrhea, headaches, sore throats, fatigue, hair loss, dermatitis, general weakness and psychological depression among other signs. In infants, these toxins pose a high risk to a chronic condition of bleeding in the lungs also known as pulmonary hemosiderosis.


This genus is an allergen designated under "Hyphomycetes." It has been known to contribute to Type I allergies like asthma & hay fever. It mainly exists in the cool northern hemisphere, grows in moist wood, soil, cellulose materials, rotting plants, and on living plants as pathogens (e.g. leaf spots). Its colonies tend to grow at a rapid pace and possess a cotton-like and velvety texture. It has a black, light brown and olive green color variety; rarely do the colonies grow indoors, but Stemphylium can do grow well in dust especially from outdoors to indoors through air filters.


Torula can be found outdoors in air, soil, on dead vegetation, wood, and grasses. Indoors, it tends to grow on cellulosic materials. Torula is said to be allergenic and may cause hay fever and asthma.


Trichoderma is a genus of fungi that is present in all soils. Many species in this genus can be characterized as allergenic, opportunistic avirulent plant symbionts. It forms toxic antibiotics harmful to humans and easily degrades cellulose. Some members of this genus are causal agents of green mold, a disease of cultivated button mushrooms. Trichoderma viride is the causal agent of green mold rot of onion.


This is an allergen that has been linked to athlete's foot, ringworm, jock itch, and similar infections of the nail, beard, skin and scalp. It grows in soil and on the skin.


A plant pathogen that grows quickly in decaying soil, vegetation, flour and corn seeds. Trichothecium roseum species are able to produce trichothecene toxins related to diseases in animals or humans. Classified as allergenic.


Ulocladium is a genus of fungi. Members of this genus contain both plant pathogens and food spoilage agents. Some species can invade homes and are a sign of moisture because the mold requires water to thrive. They can cause plant diseases or hay fever and more serious infections in immuno-suppressed individuals. Its colonies do not grow that fast and has color shades of black/gray, rusty/olive brown with velvet or granular texture.


Verticillium is a genus of fungi in the division Ascomycota, and are an anamorphic form of the Plectosphaerellaceae family. Presently, the genus is thought to contain 51 species and may be broadly divided into three ecologically based groups 1) mycopathogens 2) entomopathogens and 3) plant pathogens and related saprotrophs. It grows fast in rotting habitat, soil, straw and various arthropods and is also an occasional cause of infection found on human cornea.


Wallemia sebi is one of the so called xerophilic molds, and can therefore grow under relatively dry conditions with low water activity. Wallemia sebi has a world-wide distribution. Walemia is common in indoor environments and has been isolated from jams, dates, bread, cakes, salted beans and fish, bacon, fruits, soil, hay, and textiles. It is also common in agricultural environments where it is suspected to be one of the causes of farmer's lung disease and other human allergies. It also produces a mycotoxin called walleminol A. Although, not much is known yet about this toxin or its health effects on humans.


Mold and yeast are two groups of plants in the fungus family. Both groups can cause allergic reactions. Fungal spores can circulate in the air and may cause allergic rhinitis when inhaled. Yeasts are unicellular, although some species with yeast forms may become multicellular through the formation of a string of connected budding cells known as pseudohyphae, or false hyphae, as seen in most molds. Yeast size can vary greatly depending on the species, typically measuring 3–4 µm in diameter, although some yeasts can reach over 40 µm. Some species of yeast are opportunistic pathogens where they can cause infection in people with compromised immune systems.