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Mycology glossary

Seventy essential terms from fungal biology, cultivation, food fermentation and applied mycology, each explained in one or two sentences.

A shared vocabulary for working with fungi

Mycology borrows words from botany, microbiology, food science and engineering, and the same idea often goes by several names. This glossary gathers the terms you will meet most often in Fungaris programs, in the virtual campus readings and in the live sessions with our teaching professionals.

Terms are listed alphabetically. Definitions are deliberately short: they give you a reliable starting point, and the programs then show how each concept is applied in the lab, the grow room or the field.

Terms A to Z

70 terms

Agar: A gelling polysaccharide extracted from red algae. Mixed with nutrients such as malt extract or potato dextrose, it forms the solid medium used to grow and isolate fungal cultures in Petri dishes.
Anastomosis: The fusion of two hyphae, from the same or compatible mycelia, which links them into a connected network. It allows nuclei, cytoplasm and nutrients to move through the colony.
Annulus: The ring of tissue left on the stipe of some mushrooms when the partial veil that protected the young gills tears. Its presence and shape are useful identification features.
Arbuscular mycorrhiza: A symbiosis in which fungi of the Glomeromycota enter the root cells of a plant and form branched exchange structures called arbuscules. It is the most widespread type of mycorrhiza and occurs in most land plants, including many crops.
Ascomycete: A fungus of the phylum Ascomycota, the largest group of fungi, which produces its sexual spores inside sacs called asci. It includes morels, truffles, many yeasts and molds such as Penicillium and Aspergillus.
Ascus: A sac-shaped cell in which ascomycetes form their sexual spores, usually eight ascospores per ascus.
Aseptic technique: The set of working practices, such as disinfecting surfaces, flaming tools and limiting air movement, used to keep cultures and sterile media free from unwanted microorganisms.

Basidiomycete: A fungus of the phylum Basidiomycota, which bears its sexual spores on basidia. It includes most gilled mushrooms, boletes and polypores, as well as rusts and smuts.
Basidium: A usually club-shaped cell on which, after nuclear fusion and meiosis, basidiomycetes produce their spores, typically four per basidium.
Beta-glucan: A polysaccharide made of glucose units joined by beta-glycosidic bonds that forms part of the fungal cell wall. Beta-glucans from fungi and cereals are studied in nutrition and immunology research.
Biological efficiency: A yield measure in mushroom cultivation: the fresh weight of mushrooms harvested divided by the dry weight of the substrate, expressed as a percentage.
Brown rot: A type of wood decay in which fungi break down cellulose and hemicellulose but leave a modified lignin behind. The wood turns brown and cracks into cubical pieces.
Bulk substrate: A large volume of substrate, such as pasteurized straw or a coir-based mix, that is inoculated with spawn to produce mushrooms.

Casing layer: A moist, low-nutrient layer, often peat with lime, spread over colonized substrate. It retains water and hosts microbes that help trigger fruiting, and is essential for button mushrooms (Agaricus bisporus).
Chitin: A tough polymer of N-acetylglucosamine that gives the fungal cell wall its structure. The same molecule forms the exoskeletons of insects and crustaceans.
Clamp connection: A small hook-shaped bridge formed at the septa of many dikaryotic basidiomycete hyphae. It ensures that each new cell receives one of each of the two nuclei and is a useful microscopic feature.
Colonization: The growth of mycelium through a substrate or medium until it is fully occupied. A well-colonized substrate is less vulnerable to contaminants.
Contamination: The presence of unwanted organisms, such as Trichoderma molds or bacteria, in a culture, spawn or substrate. It competes with the desired fungus and is the main cause of losses in cultivation.

Dikaryon: A mycelium whose cells each contain two genetically different nuclei, formed after two compatible monokaryons fuse. In most basidiomycetes it is the stage able to form fruiting bodies.

Ectomycorrhiza: A mycorrhiza in which the fungus wraps the root tips in a mantle and grows between the root cells without entering them. It links trees such as oaks, pines and beeches with fungi such as boletes, chanterelles and truffles.
Endophyte: A fungus that lives inside plant tissues for at least part of its life cycle without causing visible disease. Some endophytes help their host tolerate stress or deter herbivores.
Ergosterol: The main sterol in fungal cell membranes, playing a role similar to cholesterol in animals. Exposed to ultraviolet light it is converted into vitamin D2.

Fermentation: The transformation of food or other materials by microorganisms such as yeasts, molds and bacteria. Fungal fermentations give us bread, beer, wine, koji, miso and tempeh.
Flush: A wave of mushrooms that develop and mature at roughly the same time. A substrate usually produces several flushes separated by resting periods.
Fruiting body: The multicellular structure a fungus builds to produce and release spores. Mushrooms, truffles and brackets are fruiting bodies; the mycelium is the rest of the organism.
Fruiting chamber: An enclosure or room where humidity, fresh air exchange, light and temperature are controlled to induce and support mushroom formation.
Fungi: A kingdom of eukaryotic organisms that feed by absorbing nutrients and have cell walls containing chitin. They are more closely related to animals than to plants.

Grain spawn: Sterilized cereal grain, such as rye, wheat or millet, fully colonized by mycelium. Each grain acts as an inoculation point when mixed into a bulk substrate.

Hartig net: The network of hyphae that grows between the outer root cells in an ectomycorrhiza. It is the main site of nutrient exchange between fungus and tree.
Hymenium: The fertile layer of a fruiting body in which basidia or asci form. It lines the gills, pores, teeth or surface of the fruiting body.
Hypha: A microscopic, tubular filament that grows at its tip and is the basic building unit of most fungi. Many hyphae together form the mycelium.

Inoculation: Introducing a fungus, as spores, tissue, liquid culture or spawn, into a sterile medium or a prepared substrate.

Koji: Steamed rice, barley or soybeans cultured with the mold Aspergillus oryzae. Its enzymes break down starch and protein and are the basis of sake, miso and soy sauce.

Lamellae: The gills: thin, blade-like plates on the underside of the cap of many mushrooms, covered by the spore-producing hymenium.
Laminar flow hood: A workstation that blows HEPA-filtered air in a steady, uniform stream across the work surface. It greatly reduces airborne contamination when handling cultures.
Lichen: A composite organism formed by a fungus living in partnership with a photosynthetic partner, an alga or a cyanobacterium. The fungus provides structure and the partner supplies sugars.
Lignin: A complex aromatic polymer that stiffens plant cell walls and makes wood resistant to decay. White-rot fungi are among the few organisms that can break it down efficiently.
Liquid culture: Mycelium grown in a sterile liquid nutrient solution, for example with malt extract or sugars. It is used to inoculate grain or other sterile substrates quickly.

Monokaryon: A mycelium whose cells contain a single type of haploid nucleus, usually arising from one germinating spore. In most mushroom-forming basidiomycetes it must mate with a compatible monokaryon before it can fruit.
Mold: An informal name for filamentous fungi that grow as visible, often fuzzy colonies on food and other surfaces, such as Penicillium, Aspergillus and Rhizopus.
Mushroom: The conspicuous, often fleshy fruiting body of certain fungi, typically with a cap and a stipe. It is only the reproductive part of a much larger mycelium.
Mycelium: The network of branching hyphae that forms the feeding body of a fungus. It grows through soil, wood or substrate and can persist for many years.
Mycelium composite: A material made by growing mycelium through agricultural residues inside a mold and then drying or heat-treating it to stop growth. It is used for packaging, insulation and design objects.
Mycology: The scientific study of fungi, including their biology, ecology, genetics, uses and interactions with people, plants and animals.
Mycoremediation: The use of fungi to degrade, transform or capture pollutants such as petroleum hydrocarbons, dyes or some pesticides. Results depend strongly on the species, the pollutant and the site conditions.
Mycorrhiza: A mutualistic association between a fungus and plant roots. The fungus supplies water and mineral nutrients such as phosphorus and nitrogen, and receives carbohydrates from the plant.
Mycotoxin: A toxic secondary metabolite produced by certain molds, such as aflatoxins or ochratoxin A, that can contaminate food and feed. Toxins of poisonous mushrooms are usually classed separately.

Parasitic fungus: A fungus that obtains its nutrients from a living host and harms it in the process. Examples include honey fungus (Armillaria), rusts and insect pathogens such as Cordyceps.
Pasteurization: Heating a substrate to moderate temperatures, typically around 60-80 °C, to reduce competing organisms while keeping some heat-tolerant beneficial microbes. It is common for straw used for oyster mushrooms.
Petri dish: A shallow, lidded dish of glass or plastic used to hold agar media for growing, isolating and observing cultures.
Pileus: The cap of a mushroom, which carries the gills, pores or teeth on its underside.
Polypore: A fungus that releases spores through pores instead of gills, often forming tough brackets on wood. Many, such as Trametes and Ganoderma, are important wood decomposers.
Primordia: The first visible stage of developing fruiting bodies, often called pins. Their formation is triggered by changes in humidity, fresh air, temperature or light.

Rhizomorph: A root-like cord of tightly bundled hyphae that transports water and nutrients over long distances. Honey fungus (Armillaria) is known for its dark rhizomorphs.

Saprotroph: An organism that feeds on dead organic matter by releasing enzymes and absorbing the products. Most cultivated mushrooms, such as oyster and shiitake, are saprotrophs.
Sclerotium: A compact, hardened mass of mycelium that stores reserves and helps the fungus survive unfavourable conditions. The ergot of rye (Claviceps purpurea) is a well-known example.
Septum: A cross-wall that divides a hypha into compartments. Most septa have pores that still allow cytoplasm and sometimes nuclei to pass.
Spawn: Any material fully colonized by mycelium and used to inoculate a larger substrate, such as grain, sawdust or wooden dowels. It plays the role that seed plays in agriculture.
Spawn run: The incubation phase in which spawn colonizes the substrate. Conditions favor mycelial growth rather than fruiting.
Spore: A microscopic reproductive unit that can germinate into new hyphae. Fungi release spores in enormous numbers and disperse them by air, water or animals.
Spore print: The deposit of spores obtained by leaving a mature cap gills-down on paper or glass for several hours. Its color is an important identification feature.
Sterilization: The elimination of all living microorganisms, including heat-resistant bacterial endospores, usually with steam under pressure at 121 °C. It is required for nutrient-rich substrates and agar media.
Stipe: The stem of a mushroom, which raises the cap so that spores can be released into moving air.
Strain: A genetically distinct lineage within a species, maintained in culture, with consistent traits such as yield, temperature range or appearance.
Substrate: The material on which mycelium grows and from which it takes its nutrients, such as straw, sawdust, logs, compost or grain.
Supplementation: Adding nutrient-rich materials such as wheat bran or soybean hulls to a substrate to raise yields. It also increases the risk of contamination, so supplemented substrates are normally sterilized.

Tissue culture: Cloning a fruiting body by placing a small piece of its internal tissue on sterile agar. The resulting culture keeps the genetics of that specimen.

Volva: A cup-like sac at the base of the stipe, the remnant of the universal veil that enclosed the young mushroom. It is a key feature of Amanita, a genus that includes deadly species.

White rot: A type of wood decay in which fungi break down lignin as well as cellulose, leaving pale, fibrous wood. Oyster mushrooms, shiitake and Trametes are white-rot fungi.

Yeast: A fungus that lives mainly as single cells and multiplies by budding or fission. Saccharomyces cerevisiae, used for bread, beer and wine, is the best-known example.

From vocabulary to practice

Knowing a word is only the first step. In Fungaris programs these concepts are worked through in live online sessions with professionals who use them every day, and then applied in exercises and a final project.

Biology and identification: hyphae, septa, clamp connections, spore prints and the structures used to tell species apart.
Cultivation: agar work, liquid culture, spawn, substrates, sterilization, pasteurization and fruiting conditions.
Applied mycology: fermentation, mycelium composites, mycoremediation and the ecology of mycorrhizal fungi.

Never eat a wild mushroom based on a glossary or a photograph: reliable identification requires training and, when in doubt, an expert.

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