Mold Glossary

While there are thousands of mold species, some more commonly affect our clients’ homes than others. These species often thrive in areas that are currently moist or in areas that have previously been damaged by water. This glossary is an excellent educational resource, but the best way to determine with certainty what type of mold is growing in your home is to schedule a professional inspection.


Chaetomium is a mold genus that has 95 unique species. All of the species thrive in very wet environments. Because of this, it is found growing in areas that have been wet for awhile or that have been exposed to excessive moisture recurrently. Chaetomium grows on wood, drywall and other surfaces. It is known to cause minor to severe allergic symptoms and other serious health issues.


There are more than 700 unique species of Cladosporium. This mold is commonly found in outdoor air, but it can also grow on living or decaying vegetation. Inside the home, these species can also grow around air vents and ducts, near windows and in the bathroom. In addition to causing allergic symptoms and respiratory distress in humans, Cladosporium may cause skin and nail infections.


Stachybotrys grows in very moist areas and is known as one of the more serious types of mold to contend with indoors. Because of its slow growth rate, it usually grows on drywall, wood and other surfaces that have been moist for a lengthy period of time. This type of mold can also grow in areas that are repeatedly exposed to high levels of moisture. Both black mold and toxic black mold are species of Stachybotrys.

Penicillium & Aspergillus

The Penicillium and Aspergillus genus groups each have more than 200 known species. Uniquely, these molds can tolerate and even thrive in a wider range of environmental conditions than many other species can. They also can consume a wider range of materials. Because of these factors, Penicillium and Aspergillus are both very common in indoor and outdoor settings. Exposure to these molds can result in allergic symptoms and a variety of other illnesses.


Curvularia is a genus of mold species that often grow outdoors in soil. The spores can also be found in the air. These species can tolerate heat well, but they do require substantial moisture to thrive. When they grow inside a home, they are usually found on wood features in a moist area. The most common physical responses that humans have to exposure to Curvularia are allergic symptoms.


Epicoccum is a genus of mold species that usually grows on wood materials and plant debris outside. It may also may grow on rotting food and in soil. Inside the home, you may find Epicoccum growing on wallpaper, upholstery, paintings an many other surfaces. When environmental conditions are optimal, the mold spores will become airborne. Hay fever, asthmatic symptoms and other allergic responses are common when humans are exposed to Epicoccum.


Memnoniella shares may traits with Stachybotrys, but the unique features of its spores separate Memnoniella from Stachybotrys. In outdoor settings, Memnoniella is found in the air as well as on plants and in the soil. Inside homes, it grows on upholstered surfaces, wallpaper, paper and even decaying plants in pots. Because these spores are relatively dry, they can become airborne easily and spread throughout the home. It may cause a wide range of mild to serious physical symptoms in humans who are exposed to it.


Alternaria is a genus of mold species that is a well-known plant pathogen. It is most frequently found growing on moist soil and decaying plant matter. When the spores dry out, they become airborne and spread to other areas easily. When Alternaria is found indoors, it is usually discovered in very moist areas. Exposure to Alternaria can cause health issues that range from allergies to pneumonia.


Tetraploa is a relatively small genus that usually grows outside. Specifically, it thrives at the ground level. Because of this, it is found on the top of soil as well as on the bases of various types of plants. It is rarely found indoors. Exposure to Tetraploa may lead to skin and nail infections.


Trichoderma is a group of several dozen species of fast-growing molds. These species are often yellow, white or green. In outdoor environments, they often grow on sweet potatoes, citrus fruits, grains, tomatoes, soil and decaying vegetation. Trichoderma is not common indoors. When it is found indoors, it is usually on damp paper or wood. Notably, these mold spores can spread when they are both wet and dry. In healthy individuals, exposure to Trichoderma may lead to allergy-like symptoms and an increased asthmatic response. In people who are immunocompromised, mild to serious infections may develop.


Spegazzinia mold spores have only been found living outdoors. Primary habitats include plants, soil and trees. Because Spegazzinia has never been found indoors, its effects on human health have not been researched.


Ulocladium is a genus of common mold species that thrive in both indoor and outdoor environments. Outside the home, Ulocladium spores grow on decaying plants, dung, soil and grass. Inside, they can grow on paper, paint, wood materials, carpet backing, drywall and upholstery. While these mold spores can grow on a wide variety of surfaces, they require a substantial amount of moisture to thrive. In addition to causing an allergic response in some people, exposure could result in skin infections. Some people have a cross-reaction with Ulocladium and Alternaria that is more severe.

Hyphal Fragments

Through a mold test, the presence of hyphal fragments may be discovered. This is a term that describes the stem of the spores. Generally, spore types are determined based on the traits of the spores. When these spores are not present, identifying the exact mold type is not possible. Often, spore growth is stymied in a lab environment. Because of this, hyphal fragments are most commonly found in lab cultures.