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ABSCISSION - separation, as of conidia from a conidiophore.

ABSORB - to obtain food by taking up water and dissolved substances across a membrane; this is how fungi operate. This is also called OSMOTROPHIC NUTRITION (cf. INGEST).

ACERVULAR CONIDIOMA (ACERVULUS)  - a flat, covered, spore-producing structure developed by Coelomycetes; often subcuticular or subepidermal in plant tissue. The covering is of host material, and splits open at spore maturity.

ACROPETAL - describes chains of conidia in which the youngest conidium is at the tip of the chain; a pattern of apical growth.

ACTIVE TRANSPORT - the pumping of a substance across a cellular membrane from a point of lower concentration to one of higher concentration; requires energy.


AECIA (sing. = AECIUM) - pustules of rust fungus containing aeciospores.

AECIOSPORES - the dikaryotic `transfer' spores of Uredinales, which are formed on the alternate host in macrocyclic rusts, but can infect only the primary host.

AERO-AQUATIC FUNGI - pond-inhabiting fungi producing elaborate floating propagules which are on hand to colonize autumn-shed leaves as they fall into the water, then `condition' them in near-anaerobic conditions at the bottom of the pond (cf. AMPHIBIOUS fungi).

AEROBIC - requiring free oxygen for respiration.

AEROBIOLOGY - the study of fungal (and other) propagules in the atmosphere. This has particular relevance for plant pathologists and for people with respiratory allergies. 

AFLATOXIN - virulent toxin produced by the Hyphomycetes, Aspergillus flavus and A. parasiticus, growing on foodstuffs, esp. nuts: highly carcinogenic.

AGAR - phycocolloid produced by the red alga, Gelidium; used to solidify culture media used in mycology and bacteriology.

AGARIC - a gill- or tube-bearing mushroom of the order Agaricales (Holobasidiomycetes).

AIDS - Acquired Immune Deficiency Syndrome, an ultimately fatal condition produced when a virus destroys the T cells of the body's immune system; AIDS patients are attacked and sometimes killed by opportunistic fungi.

ALGAE (sing. = ALGA) - unicellular or simple multicellular organisms with chlorophyll, lacking the multicellular sex organs typical of plants. Include several phyla from three Kingdoms, Chromista, Protozoa, plus the prokaryotic `blue-green algae' (Cyanobacteria).

ALIMENTARY TOXIC ALEUKIA (ATA) - a mycotoxicosis caused by T-2 toxin (q.v.) which killed many people in Russia during and after World War II.

ALKALOIDS - nitrogen-containing organic compounds produced by plants; physiologically active in vertebrates; many have a bitter taste and some are poisonous.

ALLANTOID - sausage-shaped.

ALLELE - one of the two or more alternative states of a gene that occupy the same position (locus) on homologous chromosomes; alleles are separated from each other at meiosis.

ALLERGY - hypersensitivity, often to external agents, in which mast cells of the immune system initiate inflammation.

ALTERNATE HOST - the second host of heteroecious rusts: that which does not bear the sexual state (the teliospores); see PRIMARY HOST.

ALTERNATION OF GENERATIONS - succession of haploid and diploid thalli in the life cycle.

AMANITINS - see AMATOXINS; the cause of most fatal mushroom poisonings (see BASTIEN TREATMENT).

AMATOXINS - cyclic octopeptides (including " - and $ -amanitin) found in some spp. of Amanita, Galerina; extremely toxic to humans.

AMBIMOBILE - describes systemic fungicides which can move upward in the xylem or downward in the phloem.

AMBROSIA FUNGI - symbiotic wood-inhabiting fungi associated with wood-wasps and wood-inhabiting beetles; the fungi feed the larvae, and are dispersed by the adults.

AMEROSPORES - non-septate (single-celled) spores.

AMOEBOID - without a cell wall or a definite shape, moving and feeding by means of pseudopodia (temporary cytoplasmic protrusions).

AMORPHOUS - shapeless, formless.

AMPHIBIOUS FUNGI - specialized stream-inhabiting, leaf-colonizing fungi which have aquatic anamorphs often producing tetraradiate conidia (q.v.), and emergent or terrestrial teleomorphs.

AMPHOTERICIN-B (Fungizone) - an antifungal polyene antibiotic derived from actinomycetes (Streptomyces spp.); used to treat systemic mycoses.

AMYLASE - an enzyme which hydroyzes starch.

AMYLOID - turning blue in iodine (Melzer's reagent, q.v.), reacting like starch, as do many ascus tips, basidiospore walls or ornamentations; I+.

ANAEROBIC - describing cells which can live without oxygen and utilize another substrate, e.g., sulphur, as an electron acceptor. The relatively recently discovered, atypical chytridiomycetes, Callimastix and allies, are unusual among fungi in being obligate anaerobes. Most fungi are AEROBIC.

ANALOGOUS - of similar form and/or function, but of different evolutionary origin; see HOMOLOGOUS.

ANAMORPH - the asexual reproductive manifestation of a fungus: usually produces conidia, but may also be sclerotial.

ANASTOMOSIS - fusion of somatic hyphae; characteristic of Dikaryomycota.

ANDROSTENOL - mammalian pheromone produced by truffles.

ANEUPLOID - having a chromosome number which is not a multiple of the haploid set.

ANION - a negatively charged ion.

ANISOGAMY - fusion of gametes of different size, as in Allomyces (Blastocladiales: Chytridiomycota).

ANNELLIDIC - describes blastic conidia produced in sequence by short percurrent extensions of a conidiogenous cell, which leave annular scars (annellations) on the cell.

ANNULUS - a ring around the stem of mushrooms, the remains of the partial veil.

ANTABUSE (Disulfiram) - substance which, for several days after it has been ingested, will interrupt the catabolism of alcohol at the acetaldehyde stage, causing headache, numbness of extremities, metallic taste, palpitation, nausea, vomiting, blurring of vision; used to treat chronic alcoholism; see COPRINE.

ANTHERIDIUM (pl. = ANTHERIDIA) - male gametangium.

ANTIBIOTIC - a diffusible substance produced by one microorganism that is damaging to others, thereby conferring a competitive advantage on the producer.

ANTICHOLINERGIC - interfering with the transmission of nerve impulses.

APHERESIS - fractionation of blood by centrifugation, so that specific components can be replaced.

APICAL APPARATUS or APICAL RING - a specialized structure found in the tips of many unitunicate-inoperculate asci, acting as a valve or sphincter that controls the forcible expulsion of ascospores.

APICULATE - having an apiculus, a small pointed projection at the tip.

APOPLASTIC - describing the movement of substances via the cell walls: not entering the living cells (cf. SYMPLASTIC).

APOTHECIAL ASCOMA (APOTHECIUM) - the usually cup- or saucer-like ascoma of the `discomycetes'; the hymenium is exposed at maturity, as in cup fungi and morels.


APPLE SCAB - disfiguring disease of apple leaves and fruit caused by the Spilocaea pomi anamorph of Venturia inaequalis (Dothideales: Ascomycetes).

APPRESSORIUM - a swelling on a germ-tube or hypha, which adheres to the surface of a host, and facilitates subsequent penetration.


ARBUSCULE - a finely branched organ produced by endomycorrhizal fungi (Glomales) inside host root cells; the interface at which fungus and plant exchange phosphorus and photosynthates.

ARCHAEASCEOUS - (of asci) essentially bitunicate, splitting at the tip; part of the inner wall may protrude; common in lichens, esp. Lecanorales.

ARCHAEBACTERIA - an ancient line of bacteria, including the methanogenic, halophilic and thermoacidophilic groups found in hot springs and sea-floor vents; their ribosomes are distinctive, and they also differ from eubacteria (q.v.) in their ribosomal RNA, wall chemistry, and lipids.

ARTHRIC - describes thallic conidia which form by the breaking up of fertile hyphae at the septa.

ASCOGENOUS HYPHAE - the restricted dikaryophase of Ascomycetes; the dikaryotic hyphae which grow out from the fertilized ascogonium and eventually give rise to asci.

ASCOGONIUM (pl. = ASCOGONIA) - in many ascomycetes, the female gametangium that receives nuclei from the antheridium.

ASCOMA (pl. = ASCOMATA) - any multihyphal structure producing asci; formed by the Ascomycetes; see APOTHECIAL, CLEISTOTHECIAL, PERITHECIAL, PSEUDOTHECIAL ASCOMATA.


ASCOMYCOTINA - Subphylum of Dikaryomycota; form endogenous meiospores in asci and have a restricted dikaryon; generally called Ascomycetes.

ASCOSPORE - meiospore produced in an ascus; usually 8 per ascus (though the number can also be 1, 2, 3, 4, 16, 32, 64, 128, 256, 512. 1024 and 2048)

ASCUS (pl. = ASCI) - the meiosporangium of the Ascomycetes: originally evolved as a spore-gun in terrestrial environments.

ASEPTIC - free or freed from contaminating organism(s); (of microbiological technique) pertains to working under sterile conditions and using sterile techniques, e.g., working in a laminar flow bench, using flame sterilized inoculating loops and instruments.

ASEXUAL REPRODUCTION - a form of reproduction neither preceded nor followed by meiosis; in fungi, commonly involves mitospores, such as, sporangiospores or conidia. 

ASPERGILLOMA - a `fungus ball' composed principally of hyphae of Aspergillus, found in a pre-existing cavity (esp. in an upper lobe of the lung) or a bronchus; usually relatively benign or asymptomatic (cf. ASPERGILLOSIS).

ASPERGILLOSIS - any disease in man or animals caused by Aspergillus (esp. A. fumigatus).

ASYMPTOMATIC - not showing any clinical manifestations.

ATHLETE'S FOOT - irritation of the skin between the toes caused by dermatophytes (conidial anamorphs of the Arthrodermataceae, Onygenales: Ascomycetes).

ATOPIC - susceptible to developing allergies.

ATP (ADENOSINE TRIPHOSPHATE) - the major source of usable chemical energy in metabolism; on hydrolysis, ATP loses one phosphate to become adenosine diphosphate (ADP), releasing usable energy.

ATTENUATED - (1) tapered, narrowed; (2) (of a pathogen) having reduced pathogenicity or virulence.

AUTOCLAVING - sterilization by steam under pressure (15 lb./in2) for prescribed time periods; better than dry heat, as sterilization is achieved at lower temperatures (121C).

AUTOECIOUS - describes rust fungi (Uredinales) which complete their life cycle on a single host (cf. HETEROECIOUS).

AUTOIMMUNE DISEASES - diseases caused by the body's immune system attacking its own tissues or organs, e.g. rheumatoid arthritis, juvenile diabetes, lupus.

AUTOLYSIS - self-digestion resulting in cell breakdown and often liquefaction.

AUTOTROPHIC - capable of synthesizing energy-rich carbon compounds.

AUXILIARY CELL - cell from which the extramatrical spores of Gigaspora and Scutellospora (Glomales: VAM fungi) arise.

AUXINS - plant growth hormones; some are produced by ectomycorrhizal fungi.

AUXOTROPH - a biochemical mutant deficient for one or more substances; it will grow on minimal medium only if it has been supplemented with these substances.

AXENIC - describes a condition in which an organism grows alone, with no other organisms (host, symbionts or parasites) present, as in `axenic culture'.

AZYGOSPORES - extramatrical spores of some VAM fungi that resemble zygosporangia, but are not the result of any sexual process.

BALLISTOSPORE - a forcibly discharged spore.

BASAUXIC - growing from the base, rather than at the apex.

BASIDIOMA (pl. = BASIDIOMATA) - any multihyphal structure producing basidia; formed by most basidiomycetes, e.g., mushroom, puffball.


BASIDIOMYCOTINA - Subphylum of Dikaryomycota (q.v.) forming exogenous meiospores on basidia, and have an extended dikaryon; generally called Basidiomycetes.

BASIDIOSPORES - exogenous meiospores produced on a basidium; usually 4 per basidium.

BASIDIUM - the meiosporangium of the subphylum Basidiomycotina; produces exogenous meiospores (usually 4, sometimes more, occasionally 2) on special projections called sterigmata.

BASIPETAL - describes a chain of conidia to which new units are added at the base (cf. ACROPETAL).

BASTIEN TREATMENT - an apparently successful treatment for amanitin poisoning, involving: (1) twice-daily injection of 1 g vitamin C, (2) 2 capsules of nifuroxazide, three times a day, (3) two tablets of dihydrostreptomycin, three times a day, (4) penicillin therapy, (5) maintenance of fluid and electrolyte balance.

BATCH CULTURE - the growth of microorganisms in a fixed volume of medium.

BENOMYL (Benlate) - the first successful systemic fungicide: one of the Benzimidazoles, has very low toxicity to plants and animals, and controls ascomycetous fungal pathogens by interfering with spindle formation during nuclear division.

BENZIMIDAZOLES - systemic fungicides, including Benomyl (q.v.).

BIFLAGELLATE - having two flagella, as in zoospores of the Oomycota (see also HETEROKONT)..

BINDING HYPHAE - thick-walled, narrow, highly branched, non-septate hyphae found only in trimitic basidiomata (cf. SKELETAL, GENERATIVE hyphae).

BINOMIAL (or BINOMINAL) - the unique double name given to each known species: composed of generic epithet and a species, or `trivial', epithet.

BIOCIDE - a substance which kills living organisms.

BIOCONTROL - the control of undesirable organisms by other organisms.

BIOCONVERSION - the enzyme-mediated conversion of organic substrates, such as cellulose, to other more valuable substances, such as protein, by other organisms.

BIODEGRADABLE - capable of being broken down by microorganisms (bacteria and/or fungi).

BIOLOGICAL ACCUMULATION - the acccumulation of toxic substances, e.g., DDT, in higher levels of the food web by consumption of organisms of the same or lower levels which have acquired the substance but which have not been affected by it.


BIOMASS - the total mass (amount) of living organism(s) in a particular area or volume.

BIOTECHNOLOGY - the large-scale exploitation of microorganisms, including fungi, to produce pharmaceuticals, feedstuffs, or other valuable metabolites.

BIOTROPHIC - growing on another living organism, in intimate asssociation with its cytoplasm.

BIPOLAR - (1) describes a system of heterothallism in which sexual compatibility is controlled by many different alleles which occur at a single locus (cf. TETRAPOLAR); (2) describes yeasts in which budding occurs at opposite ends of the long axis of the cell, by percurrent extension: they are blastic-annellidic.

BIRD'S NEST FUNGI - members of the order Nidulariales (Gasteromycetes): the basidiospores are in peridioles (`eggs') and the `nest' is a splash-cup dispersal mechanism.

BITUNICATE - describes a type of ascus with two distinct, persistent wall layers: the `jack-in-a-box' ascus that is diagnostic of the Bitunicatae and is found in pseudothecial ascomata (cf. UNITUNICATE).

BLASTIC - one of two basic modes of conidium development: there is marked enlargement of a recognizable conidium initial before the initial is delimited by a septum; derived from budding (cf. THALLIC).

BLASTOMYCOSIS - a disease in man caused by Blastomyces dermatitidis (teleomorph in Ajellomyces dermatitidis).

BLIGHT - a general name for many diseases of plants esp. when leaf damage is sudden and serious, e.g., potato blight, late blight (Phytophora infestans); early blight (Alternaria solani).

BLISTER RUSTS - serious diseases of pines, caused by species of Cronartium (Uredinales: Teliomycetes).

BLUE CHEESES - cheeses ripened and flavoured by Penicillium roquefortii (Hyphomycetes), e.g., Roquefort, Stilton, Gorgonzola, Danish Blue.

BLUE MOULD - a downy mildew of tobacco, caused by Peronospora tabacina (Peronosporales: Oomycota).

BLUE STAIN - a blue-grey colouration of worked wood paradoxically caused by the growth of brown fungal hyphae, often those of Ophiostoma) inside the wood cells.

BLUEING REACTION - a colouration of bruised or broken tissues in some agarics (esp. Boletaceae), caused by an oxidative reaction.

BOLETE - a fleshy agaric with tubes instead of gills.

BORDEAUX MIXTURE - the first practical fungicide used by Millardet in 1883-1885 against downy mildew of grape vine (Plasmopara viticola), and still in general use for controlling many plant diseases; it contains 4 parts copper sulphate, 4 parts quicklime, 500 parts water.

BRACKET FUNGI - corky or woody, often perennial, basidiomata of the polypores (Aphyllophorales: Basidiomycetes). Also known as SHELF FUNGI.

BROAD SPECTRUM - (of fungicides) active against a wide range of organisms.

BROMATIA - enlarged hyphal tips induced by Attine (leaf-cutting) ants in their domesticated fungus, and eaten by them.

BROWN ROT - wood rot produced by a basidiomycete that can degrade cellulose but not lignin.

BUDDING - a process of growth or multiplication by development of a new cell from a small outgrowth of the parent cell (cf. BLASTIC).

BULBIL - a small sclerotium-like structure of relatively few cells.

BULLER DROP - the tiny droplet of liquid which appears at the base of a basidiospore just before it is discharged.

CANDIDIASIS - a disease of man and animals caused by species of Candida, esp. C. albicans; also called moniliasis and candidosis.

CANKER - plant disease producing sharply delimited necrosis of cortical tissue.

CAP - the spreading, often umbrella-like, gill- or tube-bearing part of an agaric, more technically known as the pileus.

CAPILLITIUM - sterile filamentous elements among the spores in some gasteromycetes and Myxostelida.

CARBOHYDRATE - organic compound consisting of a chain of carbon atoms to which hydrogen and oxygen are attached in a 2:1 ratio, e.g., sugars, starch, glycogen, cellulose.

CARBOXAMIDES (Carboxin, Vitavax) - systemic fungicides used as seed dressing to control smut on barley and wheat.

CARCINOGENS - substances which induce cancer.

CARDINAL TEMPERATURES - the minimum, maximum and optimum temperatures of growth of an organism.

CAROTENOIDS - fat-soluble pigments including carotenes (yellow and orange) and xanthophylls (yellow).

CATABOLIC - describes metabolic chemical reactions resulting in the breakdown of complex materials and the release of energy in the metabolic process (cf. ANABOLIC).

CATION - a positively charged ion.

CELL - a unit of protoplasm containing a functional genome and often enclosed by a wall.

CELLULASE - an enzyme that can degrade cellulose; a cellulolytic enzyme.

CELLULOSE - principal polysaccharide of plant cell walls; a polymer of glucose; walls of Oomycetes are partly composed of a similar substance called `fungal cellulose'.

CENTRIOLE - cytoplasmic organelle identical to a kinetosome; found in flagellated cells of  fungi; the centriole divides and organizes spindle fibres during mitosis and meiosis.

CENTROMERE - that part of the chromosome to which the spindle fibres are attached.

CENTRUM - the structures inside an ascoma, which are concerned with development of the asci.

CEPHALODIA - delimited parts of a lichen thallus containing a blue-green alga (cyanobacterium), while the main thallus contains a green alga.

CHANTERELLE - edible species of Cantharellus (Aphyllophorales: Holobasidiomycetes).

CHEMOTAXIS - movement of a motile organism up a chemical concentration gradient (cf. CHEMOTROPISM).

CHEMOTROPISM - growth of an organism up a chemical concentration gradient.

CHESTNUT BLIGHT - a devastating disease caused by Cryphonectria (Endothia) parasitica (Diaporthales: Ascomycotina) which has almost wiped out the edible chestnut (Castanea dentata) in eastern North America.

CHITIN - the principal polysaccharide in cell walls of most fungi (but not Oomycota); a polymer of N-acetylglucosamine.

CHLAMYDOSPORE - an often thick-walled, resistant mitospore, formed by many fungi. Unlike conidia, chlamydospores are often not liberated.

CHLOROPLAST - a chlorophyll-containing plastid; the site of photosynthesis. Not found in fungi.

CHOKE - a disease of grasses caused by Epichlo� (Clavicipitales); the stroma of the teleomorph encircles the main axis of the grass and prevents it from flowering.

CHOLINERGIC - stimulating or augmenting the transmission of nerve impulses (acetylcholine is an important agent of neurotransmission across synapses).

CHROMATID - one of the two daughter strands of a duplicated chromosome which are joined by a single centromere.

CHROMATOGRAPHY - a separation technique which uses the differential rates of diffusion of different sizes of molecules in gas (GC), liquid (HPLC), on paper, and in thin layers of silicate on glass, aluminum or plastic plates (TLC). Now much used in lichenology.

CHROMISTA - one of the seven Kingdoms.  It is mentioned here because the Oomycota and the Hyphochytriomycota are atypical member groups, placed in it along with many photosynthesizing organisms including the diatoms (Bacillariophyta), the Xanthophyta, the Silicoflagellates, the Chrysophyta and the Phaeophyta (brown algae), which all have chlorophyll c, and do not store food as starch (but usually as oils). Most also produce cells that have two dissimilar flagella. 

CHROMOBLASTOMYCOSIS - fungal skin disease of humans caused by species of Phialophora (Hyphomycetes).

CHROMOSOMES - in eukaryotes, usually elongated structures in the nucleus along which the genes are located; actually long DNA molecules with associated protein; seen as several to many threads or rods which appear in contracted form during mitosis and meiosis. In prokaryotes there is only one, circular chromosome.

CHYTRIDIOMYCOTA - Phylum of simple eumycotan fungi mostly with posteriorly uniflagellate zoospores; hence, chytrid.

CIRCADIAN RHYTHMS - regular rhythms of growth and activity, which occur in an approximately 24-hour cycle.

CLAMP CONNECTIONS - short, backwardly directed branches on many dikaryotic basidiomycetous hyphae, providing a bypass for one of the nuclei produced during synchronous division of the dikaryon, insuring their equal distribution between the new cells; croziers are possible homologues.

CLASS - taxonomic rank above order, but below subphylum; suffix in fungi is -mycetes.

CLASSIFICATION - the systematic arrangement of organisms, based on everything we know about them.

CLEISTOTHECIAL ASCOMA (CLEISTOTHECIUM) - an ascoma, which is closed at maturity; the unitunicate but frequently evanescent asci are often spherical and are not arranged in an hymenium; characteristic of Eurotiales.


CLONING - producing organisms all of which contain copies of the same gene: the desired gene is removed from the donor, inserted into a vector (usually a plasmid), the vector is used to transform a host culture, then those hosts which have taken up the vector are selectively cultured.

CLUB FUNGI - members of family Clavariaceae (Aphyllophorales: Basidiomycetes) which have club-shaped basidiomata. See also CORAL FUNGI. Occasionally applied to ascomycetes because many asci are clavate..

COCCIDIOIDOMYCOSIS - deep-seated mycosis caused by Coccidioides immitis (Hyphomycetes); common in dry S.W. of U.S.A.

CODON - sequence of three adjacent nucleotides (in DNA or RNA) that form the code for a single amino acid; a sequence of codons specifies the amino acids that constitute a protein.

COELOMYCETES - anamorphic (asexual) dikaryomycotan fungi in which the conidia are produced within a protective structure, an acervular or pycnidial conidioma. 

COENOCYTIC  - describes multinucleate hyphae lacking cross-walls, as in chromistan fungi and many zygomycetes.

COENZYME - an organic molecule, which plays an accessory role in enzyme-catalyzed processes, often by acting as a donor or acceptor of a substance involved in the reaction; ATP and NAD are common coenzymes.

COFACTOR - non-protein component(s) needed by an enzyme to be functional; some cofactors are metal ions, others are coenzymes (q.v.).

COLLARETTE - the often flaring wall of a phialide distal to the conidiogenous locus.

COLONY - a discrete mycelium of a fungus, often derived from a single spore.

COLUMELLA - an often inflated continuation of the stalk into the head of a spore-producing structure; found in sporangia of Mucoraceae (Zygomycetes).

COMPATIBLE - able to undergo sexual fusion: of opposite mating types.


COMPOUND ASCOMA - a teleomorphic fructification incorporating several to many distinct ascomata on or in a single structure, as in the Clavicipitales and Xylariales.

CONDITIONING - the process by which fungi must enzymically soften up substrates like dead leaves before the detritivorous animals can eat them.


CONIDIAL FUNGI - those anamorphic expressions of Ascomycetes or Basidiomycetes which form CONIDIA {q.v.). Most MOULDS belong here. Some have no TELEOMORPH and are effectively HOLOMORPHS.

CONIDIATION - the process of producing conidia.


CONIDIOGENOUS - giving rise to conidia.

CONIDIOMA (pl. = CONIDIOMATA) - any multihyphal structure producing conidia, .e.g, synnematal, sporodochial, acervular, or pycnidial conidiomata.

CONIDIOPHORE - a specialized hypha, simple or branched, on which conidia are formed.


CONIDIUM (pl. = CONIDIA) - a non-motile fungal mitospore not formed inside a sporangium; typical of dikaryomycotan anamorphs.

CONJUGATION - the kind of sexual fusion of somatic cells seen in zygomycetes; an adaptation to the absence of motile gametes.


COPRINE - a rare amino acid found in the agaric, Coprinus atramentarius; its effects mimic those of antabuse (q.v.)

COPROPHILOUS FUNGI - fungi living on dung; include many zygomycetes, ascomycetes and basidiomycetes.

CORAL FUNGI - Hymenomycetes with highly branched, upright basidiomata, usually arising from the ground; some members of the family Clavariaceae (Aphyllophorales, Holobasidiomycetes).

CORTINA - (of agarics) a filamentous or web-like partial veil covering the mature gills; typical of the rusty-brown-spored mycorrhizal genus Cortinarius.


CROSSING-OVER (CROSSOVER) - exchange of genetic material between two homologous chromosomes by the breakage and joining of sister chromatids; occurs during meiosis (reduction division).

CROZIER - in ascogenous hyphae, a terminal hook in which conjugate nuclear division takes place just prior to nuclear fusion, meiosis, and ascus formation.

CRUCIATELY-SEPTATE - describes the basidia of order Tremellales (Phragmobasidiomycetes) which are divided into four more or less equal parts by vertical cross-walls.

CRUSTOSE - describes a lichen thallus that adheres closely to the substrate (often rock) (cf. FOLIOSE, FRUTICOSE, SQUAMULOSE, LEPROSE).

CRYPTIC - inconspicuous or hidden.

CRYPTOCOCCOSIS - a systemic mycosis caused by a basidiomycetous yeast, Cryptococcus neoformans (teleomorph in Filobasidiella neoformans).

CRYPTOGAM - a plant, fungus, or chromistan that propagates by spores rather than by seeds (fungi, algae, bryophytes, ferns).

CUITLACOCHE - the spore mass of the corn smut fungus, Ustilago maydis, as eaten by Mexicans.

CUP FUNGUS - a `discomycete' - any ascomycete with an open, shallow, cupulate apothecial ascoma; a hetergeneous grouping because the asci may be unitunicate operculate, unitunicate inoperculate, or in many lichens, bitunicate.

CUTICLE - waxy or fatty layer on outer wall of epidermal cells.

CYANOBACTERIA - prokaryotic chlorophyllous organisms often capable of fixing nitrogen; also known as 'blue-green algae.'

CYCLOHEXIMIDE (ACTIDIONE) - an antibacterial and antifungal antibiotic derived from Streptomyces, which is used in isolating fungi pathogenic to humans.

CYCLOPEPTIDES (CYCLIC OLIGOPEPTIDES) - substances formed of amino acids joined in a ring (cf. AMATOXINS, CYCLOSPORINE).

CYCLOSPORINE - a cyclic polypeptide, produced by the Hyphomycete, Tolypocladium niveum; used as an effective immunosuppressant after organ transplantation.

CYSTIDIA (sing. = CYSTIDIUM) - sterile accessory cells, frequently of distinctive shape, occurring at any surface of a basidioma, particularly the hymenium, from which they frequently project. The shaggy mane, Coprinus comatus, for example, has spacing cystidia to hold its crowded gills apart.

CYTOPLASM - all the living contents of the cell, except the nucleus.


DAMPING-OFF - a rotting of seedlings at soil level; commonly caused by species of Pythium, Phytophthora, Fusarium, and Rhizoctonia.

DECIDUOUS - falling off, as leaves that are shed in the autumn; used to describe the sporangia of downy mildew fungi (Peronosporales: Oomycota).

DEER TRUFFLE - Elaphomyces (Elaphomycetales, Ascomycetes).


DEHISCENCE - the opening of a structure to permit the escape of spores; the separation of spores from the structure that produced them.

DELIQUESCE  - to liquefy; to autolyse, as in the gills of the agaric, Coprinus, or `Prototunicate' asci.

DERMATITIS - non-contagious but often chronic skin inflammation; sometimes caused by fungal infections.

DERMATOPHYTES - anamorphs of some Onygenales (Ascomycetes), which live on keratin and can cause skin disease in humans (see MYCOSES, RINGWORM, TINEA).

DESTROYING ANGEL - the pure white agaric, Amanita virosa: ingestion of 1 mL of this fungus can prove fatal; its toxins are cyclic polypeptides, esp. amanitins.

DETRITIVORE - animal which eats organic `garbage,' dead remains of other life forms.

DEXTRINOID - staining yellowish brown or reddish brown in Melzer's reagent (q.v.).

DIAGEOTROPISM - the tendency to grow in a direction horizontal to the surface of the earth.

DICHOTOMOUS - describes branching in which the two arms are equal (as in a capital Y).

DICTYOSEPTATE - having cross-walls running horizontally and vertically, like the layers of cement between bricks (also described as muriformly septate).


DICTYOSPORES - spores which are dictyoseptate  or muriform (q.v.).

DIDYMOSPORES - one-septate spores (i.e., with two cells or compartments).

DIKARYOMYCOTA - Phylum of eumycotan fungi comprising the Subphyla Ascomycotina and Basidiomycotina and their anamorphs; characterized by hyphae with chitinous walls and perforate septa, and (usually) the occurrence of a dikaryotic phase.

DIKARYON - a nuclear phenomenon unique to phylum Dikaryomycota, in which compatible nuclei pair off and cohabit without copulating; this phenomenon is restricted to ascogenous hyphae in ascomycetes; but is the dominant phase in basidiomycetes; the paired nuclei always divide synchronously.

DIKARYOTIC - having two separate but compatible nuclei in each cell or compartment; a nuclear condition unique to the fungi.

DIMITIC - describes basidiomata constructed from two different kinds of hyphae: generative and skeletal.

DIMORPHIC - having two distinct forms, as in some fungal pathogens of humans, which are yeast-like in the host, but mycelial in culture; also sometimes used to describe sexual dimorphism; having an anamorph and teleomorph.

DIPLOID - having two complements of haploid chromosomes in a single nucleus (a condition often labelled `2n') (cf. DIKARYOTIC).

DISCOLICHENS - lichens in which the mycobiont (fungal partner) forms apothecial ascomata.

DISCOMYCETES - cup fungi; an informal grouping of ascomycetes which mostly form unitunicate asci in apothecial ascomata, though many lichenized taxa have bitunicate or archaeasceous asci.

DITHIOCARBAMATES - organic fungicides; dimethyl- (DMDC): thiram, ferbam, ziram; ethylene-bis- (EBDC): nabam, maneb, mancozeb, zineb.

DNA (DEOXYRIBOSE NUCLEIC ACID) - carrier of genetic information in living organisms; composed of chains of phosphate, sugar molecules (deoxyribose), purines (guanine and adenine) and pyrimidines (cytosine and thymine); capable of self-replication as well as of determining RNA synthesis.

DNA LIGASE - an enzyme which repairs breaks in the phosphate backbone of DNA.

DNA SEQUENCING - determining the actual sequence of bases in parts of DNA or RNA molecules. The first fungus to be fully sequenced was Saccharomyces cerevisiae (Dijon et al., 1994. Nature 369:371)

DOLIPORE - the complex barrel-shaped septal pore apparatus found in basidiomycetes other than Uredinales and Ustilaginales.

DOMINANT - (of an allele) exerting its full phenotypic effect despite the presence of another allele of the same gene, whose phenotypic expression it blocks.

DORMANT SPRAYS - sprays used when plants are dormant, to control overwintering pathogens.

DOWNY MILDEWS - serious plant diseases caused by obligately parasitic fungi, such as Peronospora and Plasmopara (Peronosporales: Oomycota).

DRY ROT - wood-rot caused by certain basidiomycetes, e.g., Serpula lacrymans (Meruliaceae: Aphyllophorales). A misnomer, because if the wood were really dry, it would not rot.

DUAL CULTURE (POT CULTURE) - fungus plus host plant or phytobiont; the only way yet known of growing certain obligately biotrophic fungi (e.g. VAM fungi) in reasonably controlled conditions.

DUAL ORGANISMS - organisms which invariably consist of two interdependent symbionts, e.g. lichens. In fact, most plants are also dual or multiple organisms because of their intimate association with endo- or ecto-mycorrhizal fungi. The eukaryotic cell is widely believed to have arisen as a multiple symbiosis.

DUTCH ELM DISEASE - a usually fatal disease of the American elm tree, Ulmus americana, caused by Ophiostoma ulmi (Ophiostomatales: Ascomycetes); the fungus is spread by a bark-beetle vector.

EAR FUNGI - the gelatinous, edible basidiomata of the Auriculariales.

EARTH BALLS - the non-ostiolate basidiomata of the Sclerodermatales.

EARTH STARS - specialized soil-inhabiting puffballs (Lycoperdales: Gasteromycetes) in which the outer peridium splits and curls back in segments, raising the basidiospore mass (gleba) above the dead leaves, etc.

ECTOMYCORRHIZA or ECTOTROPHIC MYCORRHIZA - mycorrhiza in which a dikaryomycotan mycelium ramifies through the soil, forms a mantle around individual rootlets, and grows between cells of the root cortex, forming a Hartig net (the interface between the symbionts). The fungus exchanges phosphorus for photosynthates from the root. Many forest trees, esp. Pinaceae, Fagaceae, have ectomycorrhizal associations with agarics or boletes (cf. ENDOMYCORRHIZA); see MYCORRHIZA.

ELECTROPHORESIS - a technique which uses the differential mobility of differently charged molecules in an electric field to separate them within a stationary gel.

EMESIS - vomiting (sometimes caused by EMETICS).

ENDEMIC - natural to (always present in) one geographical region.

ENDOCRINE GLANDS - ductless glands which secrete hormones; include the pituitary, adrenal, thyroid.

ENDODERMIS - the differentiated, innermost layer of the cortex of roots, rhizomes and certain non-seedbearing vascular plant stems; surrounds the stele.

ENDOGENOUS - formed within another structure, as are the meiospores of Ascomycetes (cf. EXOGENOUS).

ENDOMYCORRHIZA  or ENDOTROPHIC MYCORRHIZA - an ancient symbiosis of fungi with green plants; hyphae gathering nutrients from the soil, esp. phosphorus, are continuous with others that grow between and within root cells and produce ARBUSCULES (q.v.); found in 90% of angiosperms and conifers, except Pinaceae; also called vesicular-arbuscular mycorrhizae (cf. ECTOMYCORRHIZA); see MYCORRHIZA.

ENDOPHYTIC FUNGI - fungi (such as some anamorphs of Clavicipitales) which grow systemically within plants without causing symptoms; now known to produce neurotoxins that discourage herbivores, and therefore to be participating in a mutualistic symbiosis.

ENDOPLASMIC RETICULUM (er) - extensive system of membranes in eukaryotic cells.

ENDOSYMBIONT  - an organism which lives in a mutualistic symbiosis within the cells of another organism.

ENTOMOGENOUS - living in or on insects, esp. as pathogens.

ENTOMOPATHOGENIC  - causing disease in insects.

ENZYME - a protein that, even in low concentration, speeds up (catalyzes) specific chemical reactions; usually becomes inactivated or unstable at high temperatures; name usually derived from substrate or function, with suffix -ase; see AMYLASE, CELLULASE, DNA LIGASE, PROTEASE, RESTRICTION ENDONUCLEASE. CONSTITUTIVE enzymes are produced even in the absence of the substrate; ADAPTIVE enzymes are not produced until the presence of the substrate has been recognized.

EPIDEMIC - (of disease) prevalent and spreading rapidly among many individuals in an population at the same time.

EPIDERMIS - the surface tissue of plant organs, composed of living parenchyma cells.

EPIGEOUS - fruiting above the surface of the ground (cf. HYPOGEOUS).

EPIPHYTOTIC - an unnecessary coining meaning an EPIDEMIC among plants.

EPITHET - one of the words which makes up the binomial of an organism.

EPIZOOTIC - an unnecessary coining meaning an EPIDEMIC among animals.

ERADICANT - a fungicide which can kill a pathogen both outside and inside the host, because it is systemic (cf. PROTECTANT).

ERGOMETRINE (D-lysergic acid propanolamide) - an alkaloid of Claviceps purpurea sclerotia; used to induce labour.

ERGOT - (1) a disease of cereals and grasses, caused by species of Claviceps, esp. ergot of rye (C. purpurea); (2) the sclerotium of the ergot fungus, which contains many toxic and psychogenic alkaloids.

ERGOTAMINE - a 3-amino acid cyclopeptide derivative of lysergic acid from Claviceps purpurea sclerotia; ergotamine tartrate is used to manage migraine by causing vasoconstriction of cranial arterioles, thereby reducing the pulsation pressure and attendant headache.

ERGOTISM - ergot poisoning, of two main types in man: the gangrenous and the convulsive; historically known as `St. Antony's Fire'.

ERYTHROCYTES - red blood cells.

ETIOLATED - (of plants) excessively tall and lacking chlorophyll.

ETIOLOGY - the cause or origin of a disease.

EUBACTERIA - all bacteria which are not archaeobacteria; include all gram-positive bacteria with peptidoglycan walls, all gram-negative bacteria, all photosynthetic bacteria, all bacteria without a rigid cell wall.

EUCARPIC - with thallus divided into vegetative and reproductive structures (cf. HOLOCARPIC).

EUKARYOTIC - having nuclei which are delimited by nuclear membrane, contain an even number of discrete chromosomes, and divide mitotically: the cytoplasm also contains organelles, such as mitochondria (cf. PROKARYOTIC).

EUMYCOTA - the Kingdom to which the phyla Chytridiomycota, Zygomycota and Dikaryomycota belong.

EVANESCENT - short-lived, soon disappearing.

EXOCRINE GLANDS - those which release their secretions through ducts, e.g. salivary glands, sweat glands, lachrymal (tear) glands.

EXODERMIS - in plant roots, the layer of cells immediately inside the epidermis; cells may be dimorphic, and variably suberized, influencing entry of VAM fungi and pathogens.

EXOGENOUS - formed externally to the parent cell, as are the meiospores of basidiomycetes.

EXTRAMATRICAL - VAM structures (mycelium, spores) developing outside the roots of the phytobiont.

EXTRANUCLEAR INHERITANCE - transmission of genetic information in the cytoplasm by DNA present in organelles, such as mitochondria.

FACULTATIVE - (of a parasite) able to live as a saprobe (cf. OBLIGATE, OPPORTUNISTIC).

FAIRY RING - mushrooms arising at the periphery of a radially spreading underground mycelium; common in grasslands, and around conifers.

FALSE MOREL - Gyromitra esculenta (Ascomycetes), which is poisonous; see GYROMITRIN.

FALSE TRUFFLE - a hypogeous, ectomycorrhizal gasteromycete, e.g., Rhizopogon.

FAMILY - taxonomic group above genus, but below order; suffix is -aceae.

FERMENTATION - chemical changes in organic substrates caused by enzymes of living microorganisms.

FERTILIZATION - the fusion of two gametes to form a diploid zygote.

FLAGELLUM (pl. = FLAGELLA) - a long whip-like locomotory organelle projecting from a cell; found in zoospores of the chromistan Oomycota and Hyphochytriomycota; and the eumycotan Chytridiomycota. Has similar ultrastructure in all three phyla (9 peripheral tubules + 2 central tubules, all made of a contractile protein called tubulin.)

FOLIAR - relating to leaves.

FOLIOSE - describes a lichen thallus which has broad lobes free from the substrate (cf. CRUSTOSE, FRUTICOSE, SQUAMULOSE, LEPROSE).

FRUTICOSE - describes a lichen thallus which is shrub-like, erect or hanging, and branched (cf. CRUSTOSE, FOLIOSE, SQUAMULOSE, LEPROSE).

FUNGI (sing. = FUNGUS) - non-photosynthesizing (i.e., heterotrophic) eukaryotes that produce exoenzymes and absorb their food: usually producing, and living inside, a network of apically extending, branched tubes called hyphae; may belong to Kingdom Chromista or Kingdom Eumycota.

FUNGICIDE - an agent designed to kill fungi; may be chemical or biological.

'FUNGI IMPERFECTI' - an unfortunate and obsolete name for anamorphic fungi which are, or are suspected to be, the anamorphs of ascomycetes or basidiomycetes; better called `conidial fungi.' They are no less perfect than the teleomorphs some of them possess.

GAMETANGIUM (pl. = GAMETANGIA) - a single-celled structure producing gametes (sex cells) or gametic nuclei.

GAMETE - cell, motile or non-motile, which can fuse with another compatible gamete to form a zygote (e.g., sperm,[motile], spermatium, [non-motile], egg, oosphere)

GASTEROMYCETES - Holobasidiomycetes with basidioma closed at basidiospore maturity, hymenium present or absent, spore-shooting mechanism lost: basidiospores passively dispersed by a variety of interesting methods; a heterogeneous group.

GENE - a unit of heredity in the chromosome; a sequence of nucleotides in a DNA molecule that codes for a polypeptide.

GENERATIVE HYPHAE - thin-walled, branched hyphae which are the only kind found in monomitic basidiomata (cf. SKELETAL, BINDING hyphae).

GENET - an individual or colony resulting from sexual reproduction.

GENETIC RECOMBINATION - the reassortment of genes produced as a result of crossing-over during meiosis.

GENOME - the total genetic material of an organism (chromosomes plus cytoplasmic genes).

GENOTYPE - the sum of the genetic potential of an organism: in many fungi only part of this is expressed at any given time (see HOLOMORPH, ANAMORPH, TELEOMORPH).

GENUS (pl.= GENERA) - taxonomic rank below family, but above species. One genus may contain from one to thousands of species

GEOTROPIC - growing vertically downward under the influence of gravity.

GERM PORE - a differentiated, thin area, or hollow, in a spore wall through which a germ tube may emerge.

GERM SLIT - a thin area of a spore wall running the length of the spore.

GERM TUBE - the hypha that emerges from germinating spores of true fungi.

GERMINATION BY REPETITION - the production and forcible release of a secondary ballistospore by a recently released basidiospore; characteristic of the Phragmobasidiomycetes.

GILLS - flat, vertically oriented plates of tissue that bear the hymenium in most agarics; also called lamellae.

GLEBA - basidiospore mass of a gasteromycete, enclosed in puffballs, exposed in stinkhorns .

GLUCOSE - an six-carbon sugar (C6H12O6); the commonest monosaccharide in most organisms.

GLYCOGEN - an insoluble carbohydrate, similar to starch; a reserve food found in fungi, bacteria and animals.

GLYCOLYSIS - a process in which sugar is changed anaerobically to pyruvic acid, with the liberation of a small amount of usable energy.

GOLGI BODY,  GOLGI APPARATUS - an intracellular organelle that consists of flat, disc-shaped vesicles often forming tubules at the edges; sites of accumulation and synthesis of cell products, e.g., wall material; in plants, sometimes called DICTYOSOMES.

GRANULOMA - a nodule of firm tissue formed as a reaction to chronic irritation.

GRISEOFULVIN - a chlorine-containing antifungal antibiotic from Penicillium griseofulvum, and P. nigricans; has been used as a systemic fungicide against plant pathogens and orally against dermtophyte infections in animals and humans.

GYROMITRIN - a heat-labile, carcinogenic, cellular toxin produced by Gyromitra esculenta (the False Morel); breaks down to monomethylhydrazine (MMH), which is also extremely toxic.

HALLUCINOGEN - a psychoactive substance which causes disturbances of perception, e.g. psilocybin.

HAMANATTO - an Oriental food obtained by fermenting whole soybeans with Aspergillus oryzae; tao-cho (Malaysia); tao-si (Philippines); tu su (China).

HAPLOID - having a single set of chromosomes (often denoted by `n').

HARTIG NET - the intercellular hyphal network formed by an ectomycorrhizal fungus in the surface layers of a root; the effective interface between the symboints.

HAUSTORIUM (pl. = HAUSTORIA) - in parasitic fungi, a specialized absorptive structure that penetrates and draws food from the host cell.

HEART ROT - decay of the inner wood of trees, caused by basidiomycetes.

HELICOSPORE - a spore which curves through more than 180, and often through several complete gyres, coiling in two or three dimensions.

HEPATIC - concerning the liver, as in HEPATOMA (liver cancer).

HERBICIDE - a substance which kills plants.

HETEROECIOUS - describes rust fungi which need two hosts to complete their life cycle (cf. AUTOECIOUS).

HETEROKARYOTIC - containing genetically dissimilar nuclei.

HETEROKONT - having flagella of more than one kind, as in the motile cells of the Oomycota (and of many other Chromista, including the brown algae)

HETEROTHALLIC - describes fungi in which two genetically distinct but compatible mycelia must meet before sexual reproduction can take place (cf. HOMOTHALLIC).

HETEROTROPHIC - unable to derive energy from photosynthesis or from inorganic chemical reactions, and so dependent on energy-containing organic compounds derived from the current or prior existence of other organisms, cf. AUTOTROPHIC.

HETEROZYGOUS - having two different alleles at the same locus on homologous chromosomes.

HISTOPLASMOSIS - deep-seated mycosis of humans caused by Histoplasma capsulatum (Hyphomycetes); common in the Mississippi Valley.

HOLOBASIDIOMYCETES - basidiomycetes in which the basidia are not subdivided by septa (cf. PHRAGMOBASIDIOMYCETES).

HOLOBASIDIUM (pl. = HOLOBASIDIA) - a meiosporangium not divided by septa, which usually gives rise to 4 exogenous basidiospores (cf. PHRAGMOBASIDIUM).

HOLOCARPIC - with thallus becoming entirely converted into reproductive structures (cf. EUCARPIC).

HOLOMORPH - all manifestations of a genotype: in a fungus this frequently means one or more anamorphs plus teleomorph.

HOMOLOGOUS - (1) with the same evolutionary origin though now often different in form and/or function; (2) (of chromosomes) bearing genes for the same characters.

HOMOTHALLIC - describes fungi in which a single strain can undertake sexual reproduction; self-compatible (cf. HETEROTHALLIC).

HOMOZYGOUS - having identical alleles at the same locus on homologous chromosomes.

HONEY FUNGUS - the agaric, Armillaria mellea, which is parasitic on trees and causes serious root rots.

HORMONES - usually peptides or steroids, which are produced in one part of an organism and trigger specific rections in cells elsewhere.

HOST - an organism on or in which a parasitic, necrotrophic or symbiotic fungus lives.

HYDROLYSIS - splitting of a molecule into two parts by adding hydrogen and hydroxyl ions derived from water.

HYMENIUM (pl. = HYMENIA) - fertile layer in fungi; bears asci in ascomata, basidia in basidiomata, conidia in pycnidia or acervuli.

HYMENOMYCETES - Holobasidiomycetes with hymenium exposed at maturity, basidiospores shot off (cf. GASTEROMYCETES).

HYPERPARASITE - an organism that parasitizes either another parasite, or an organism closely related to itself.

HYPERSENSITIVITY - the condition in which the host tissue dies at the point of attack by a pathogen, so that the infection does not spread.

HYPERTROPHY - excessive or abnormal growth.

HYPHA (pl. = HYPHAE) - the tubular architectural module of almost all fungi, its wall chitinous in eumycotan fungi, cellulosic in oomycetes.

HYPHOCHYTRIOMYCOTA - Phylum of Chromistan fungi with anteriorly uniflagellate zoospores; hence, hyphochytrid.

HYPHOMYCETES - conidial anamorphs (mostly ascomycetous, some basidiomycetous) producing exposed conidiophores, not enclosed in any protective structure (cf. COELOMYCETES), and usually liberating CONIDIA in large numbers..

HYPOGEOUS - describes fungi which produce macroscopic fruiting bodies underground.

IBOTENIC ACID - a metabolite of Amanita muscaria; changes to muscimol, a hallucinogen, when the basidiomata are dried.

IMMUNOSUPPRESSANT - a substance, such as the fungal metabolite, cyclosporine, (produced by the hyphomycete, Tolypocladium niveum) which partially or completely suppresses the immune system; used to prevent rejection of transplanted organs.

INGEST - to obtain food by engulfing it (as opposed to absorbing, which is what fungi do) (see PHAGOTROPHIC).


INOCULATE - to put a microorganism into an organism or a substratum.

INOCULUM - a small amount of a fungus used to inoculate fresh culture medium or to infect a host organism.

INOPERCULATE - describes sporangia, esp. some unitunicate asci, which lack a specialized operculum or cap that opens to permit spore discharge (cf. OPERCULATE).

INTERCALARY - among or between cells; refers to such things as non-apical chlamydospores in many fungi.

INTRAMATRICAL SPORES - another name for the vesicles produced in host roots by most endomycorrhizal fungi.

ION - a charged atom or group of atoms.

IRRADIATION - exposure to some form of radiant energy.

ISIDIA - simple or branched protuberances of the cortex in lichens, which may break off and act as a form of vegetative propagule.

ISOGAMY - fusion of morphologically identical gametes.


JELLY FUNGI - wood-inhabiting basidiomycetes with gelatinous basidiomata; Orders: Tremellales, Auriculariales (Phragmobasidiomycetes); Dacrymycetales (Holobasidiomycetes).

KARYOGAMY - the fusion of sexually compatible haploid nuclei.

KARYOLOGY - the study of the behaviour of nuclei in eukaryotes.

KATSUOBUSHI - a Japanese fermented food; cooked bonito fish is fermented by Aspergillus glaucus until dry; the product is shaved into ribbons and used for flavouring other foods.

kb - kilobases, an abbreviation for 1000 base pairs of DNA.

KERATIN - the protein that is the main component of skin, hair, feathers and horns.

KERATINOPHILIC - capable of decomposing keratin, as are many of the fungi that cause superficial mycoses in man; see DERMATOPHYTES, RINGWORM, TINEA.

KETJAP - an Oriental fermented food; Indonesian soy sauce; black soybeans are fermented for 2-3 days by Aspergillus oryzae; the root of the words Ketchup and Catsup.

KETOCONAZOLE (Nizoral) - an antifungal antibiotic.

KINETOSOME - basal body; self-replicating organelle at the base of flagellum, similar to a centriole.

KINGDOM - the highest taxonomic category, of which 7 are currently recognized (Archaebacteria, Eubacteria, Protozoa, Chromista, Plantae, Eumycota, Animalia);  all members of Kingdom Eumycota are fungi, and two of the phyla in Kingdom Chromista are also treated as fungi. 

KOJI - a `starter' consisting of Aspergillus oryzae cultured on roasted wheat or barley (for hamanatto) or A. orzyae or A. soyae cultured on rice (for miso), which is then inoculated on the appropriate substrate.

KOMBUCHA - The following have been isolated from 'Kombucha tea' Bacterium xylinum, Bacterium xylinoides, Bacterium gluconicum, Saccharomyces ludwigii, Saccharomyces apiculatus varieties, Schizosaccaromyces pombe, Acetobacter ketogenum, Torula varieties, Pichia fermantans and other yeasts.  In other words, this is a really mixed bag which has occasionally had very deleterious effects.  I do not recommend that anyone indulge in this highly experimental 'beverage.'

KREBS CYCLE - the series of reactions that results in the oxidation of pyruvic acid to hydrogen atoms, electrons, and carbon dioxide; the electrons, passed along electron-carrier molecules, then go through the phosphorylation and terminal oxidation processes; also called the tricarboxylic acid cycle or TCA.


LD50 - LD = lethal dose; LD50 = that dose which kills 50% of the spores, cells or individuals of the test organism.

LECANORINE - lichen apothecia in which algal cells are found in the thickened margin of the fruit body.  The margin is frequently the same colour as the thallus.  cf. LECIDEINE.

LECIDEINE - lichen apothecial ascomata with no algal cells in the margin. cf. LECANORINE.  

LEPROSE - describes a kind of lichen thallus in which there is no organized cortical layer, and the thallus tends to break up into a mass of powdery soredia (mixed algal-fungal propagules).

LESION - a wound, injury, or area of diseased tissue.

LEUCOCYTES - white (non-haemoglobin-containing) blood cells of many types, including phagocytic macrophages and antibody-producing lymphocytes.

LICHEN - a dual organism in which a fungus (usually an ascomycete) maintains a green alga or a cyanobacterium captive within its thallus in a symbiosis that approaches balanced parasitism.   Some lichens consist of three or more symbionts.

LIGNIN - a polymer of phenylpropanoid units that is an important constituent of wood.  It is resistant to biodegradation by most organisms, but can be degraded by many basidiomycetes.

LIPIDS - molecules containing a fatty acid with a long hydrocarbon chain, e.g., triglycerides (ester of a fatty acid plus glycerol), phospholipids (triglyceride containing 2 fatty acid chains and phosphate as a polar group).

LIRELLATE - long and thin, as in the ascomata of some lichens.

LOCULE - a spore-containing cavity, esp. one secondarily developed within a pseudothecial ascoma, or in the basidiomata of Lycoperdales and Sclerodermatales, or in many sequestrate agarics.

LOCULOASCOMYCETES - a name sometimes applied to the ascomycetes with bitunicate asci.

LOCUS (pl. = LOCI) - (1) a specific location; (2) the position on a chromosome occupied by a particular gene, hence often used synonymously with gene.

LSD - LYSERGIC ACID DIETHYLAMIDE, a powerful hallucinogen derived from Claviceps sclerotia.

LYOPHILIZATION - freeze-drying, a technique used to preserve fungal cultures in a state of suspended animation.

MACROCYCLIC - describes rust fungi which produce all 5 developmental stages -- basidiospores, spermatia, aeciospores, urediniospores, and teliospores (cf. MICROCYCLIC).

MACRONUTRIENTS - inorganic chemical elements required in large amounts for plant or fungal growth, e.g., nitrogen, carbon, potassium, calcium, phosphorus, magnesium, and sulphur.

MACROSCOPIC - big enough to be seen by the naked eye.

MAGIC MUSHROOMS - typically, hallucinogen-containing species of Psilocybe, but also spp. of Gymnopilus, Panaeolus, Conocybe, and Amanita muscaria.

MANNITOL - a polyhydric alcohol, often found as a storage compound in ectotrophic mycorrhizal mantles.

MANTLE - a compact layer of hyphae enclosing short feeder roots of ectomycorrhizal plants; connected to the Hartig net on the inside, and to the extramatrical hyphae on the outside; acts as a sink for nutrients.

MASTIGONEMES - hair-like processes or flimmers on the surface of tinsel flagella.

MATSU-TAKE - Tricholoma matsutake; an important edible fungus in Japan; grows in ectomycorrhizal association with pines. Tricholoma magnivelare, the North American pine mushroom, is also highly prized.

MEDIUM, culture - a substance or solution for the culture of microorganisms. DEFINED MEDIUM -- of a prescribed composition, used for determining the biochemical capabilities of the organism, e.g., auxotrophs; COMPLETE MEDIUM -- containing all nutrients required for growth; MINIMAL MEDIUM -- the simplest chemically defined medium on which the wild type (prototroph) of a species will grow and which must be supplemented by one or more specific substances for the growth of auxotrophic mutants derived from the wild type; SELECTIVE MEDIUM - medium containing certain chemical components which restrict the growth of some microorganisms but encourages the growth of others.

MEIOSIS - reduction division: a diploid nucleus produced (usually) 4 haploid nuclei by 2 successive nuclear divisions in which the chromosome number is halved from diploid (2n) to haploid (n), and genetic segregation and recombination occur.

MEIOSPORANGIUM (pl. = MEIOSPORANGIA) - a sporangium within which meiosis occurs before spore formation (e.g., basidium, ascus); produces meiospores. (cf. MITOSPORANGIUM).

MEIXNER TEST - for amatoxins: (1) express fluid from agaric onto newsprint, (2) dry, (3) add a drop of concentrated hydrochloric acid, (4) blue colour developing in 1-20 mins. indicates presence of amatoxin; higher levels produce colour sooner. Not always reliable, in my experience.

MELZER'S REAGENT - used to elicit amyloid or dextrinoid reactions in spores, asci, hymenial tissues, etc.; chloral hydrate - 100 g, potassium iodide - 5g, iodine - 1.5 g, distilled water - 100 mL.

MEROSPORANGIUM (pl. = MEROSPORANGIA) - (of Zygomycetes) a cylindrical outgrowth from the swollen end of a sporangiophore in which a chain-like series of sporangiospores is generally produced.

MESOPHILIC - describes organisms which grow at temperatures between 10-40C (opt. 20-35C) (cf. PSYCHROPHILIC, THERMOPHILIC).

MESOZOIC - the geological era comprising the Triassic, Jurassic and Cretaceous period (225-65 million years before present).

METABOLISM - the sum of all chemical processes occurring within a living cell or organism; PRIMARY METABOLISM -- metabolism associated with the normal maintenance and growth of the organism; SECONDARY METABOLISM -- processes which use primary metabolites available after growth has ceased, producing substances with no known role in primary metabolism.

METAMORPHOSIS - a dramatic reorganization leading to a change in appearance, as in the developmental change from caterpillar (larva) to butterfly (imago) via the pupa..

METULAE - special cells at the apex of a complex conidiophore which support conidiogenous cells, as in many species of Penicillium, Leptographium.

mg - see MILLIGRAM.

MICROBODY - cellular organelle bounded by a single membrane, and containing enzymes; derived from endoplasmic reticulum.

MICROCYCLIC - describes rust fungi in which some stages of the life cycle are bypassed (cf. MACROCYCLIC).

MICROGRAM - one-millionth of a gram: written as `g'.

MICRON - one-thousandth of a millimetre or one-millionth of a metre: written as `m'.

MICROPORES - extremely narrow connectives penetrating the septa of some mycelial yeasts, e.g. Geotrichum.

MICROTUBULE - narrow (about 25 nanometres in diam.), elongate, non-membranous tubule of indefinite length occurring in the cytoplasm of many eukaryotic cells; the major component of the mitotic spindle and flagella; made of a protein called tubulin.

MIDDLE LAMELLA - pectin-rich layer between the walls of adjacent plant cells; this layer is attacked and dissolved by damping-off fungi.

MILLIGRAM - one-thousandth of a gram: written as `mg'.


MISO - an Oriental food product, used for soups and as flavouring agent, composed of rice and cereals + soybeans fermented by Aspergillus oryzae and Saccharomyces rouxii.

MITOCHONDRIA - intracellular organelles concerned with the Krebs cycle and electron transport: the chief source of ATP in non-photosynthesizing cells.

MITOSIS - nuclear division involving chromosomes that are replicated and distributed equally between the daughter nuclei. (cf. MEIOSIS)

MITOSPORANGIUM (pl. = MITOSPORANGIA) - a sporangium producing mitospores, characteristic of anamorphic zygomycetes (cf. MEIOSPORANGIUM).

MITOSPORE - a spore receiving a nucleus or nuclei resulting from mitotic division; characteristic of asexual reproduction; see CONIDIUM, ZOOSPORES, MITOSPORANGIUM.


MONILIOID - describes closely-septate hyphae with swollen cells, constricted at the septa.

MONOCULTURE - condition in which one species is grown in an extensive pure stand; describes most agricultural situations.

MONOKARYON - in ascomycetes and basidiomycetes, the haploid phase in which the hyphae contain only one kind of nuclei (cf. DIKARYON).

MONOMER - a simple molecule that can form polymers by combining with identical or similar molecules.


MONOMITIC - describes basidiomata constructed of only one kind of hypha, the generative type (cf. DIMITIC, TRIMITIC).

MOREL - a large, edible ascoma of the genus Morchella (Pezizales, Ascomycetes); fruits in Spring.

MOULDS - fungi, usually either zygomycetes or hyphomycetes, associated with deterioration of food or manufactured goods of organic origin.

MUCILAGINOUS - composed of mucilage.

MUCORMYCOSIS - a disease of man or animals caused by one of the Mucorales, e.g., Absidia corymbifera, but sometimes also applied to infections caused by members of the Entomophthorales.

MULTILOCULAR - with several to many internal spore-producing cavities or chambers.

MULTIPOLAR - describes yeasts in which each successive blastic conidium arises from a different point on the mother cell.

MUSCARDINE DISEASES - diseases of certain insects, esp. silkworms, caused by hyphomycetes; GREEN MUSCARDINE -- Metarhizium anisopliae; WHITE MUSCARDINE -- Beauveria bassiana; YELLOW MUSCARDINE -- Paecilomyces farinosus.

MUSCARINE - toxic quaternary ammonium compound found in species of Clitocybe and Inocybe; causes perspiration-salivation-lacrymation syndrome.

MUSCIMOL - a hallucinogenic derivative of ibotenic acid; formed in Amanita muscaria when basidiomata are dried.

MUSHROOM - a fleshy basidioma, usually stalked and with a cap (pileus) beneath which gills or fleshy tubes are covered with or lined with the hymenium; edible or poisonous; see AGARIC, BOLETE.

MUTAGEN - an agent that increases the mutation rate.

MUTATION - a permanent change in a gene.

MUTANT - a mutated gene, or an organism carrying a gene that has undergone a mutation; may be biochemical, fermentation, resistance, suppressor, physiological, in nature.

MUTUALISM (MUTUALISTIC SYMBIOSIS) - a kind of symbiosis in which both or all partners gain from the association, e.g. mycorrhizae.

MYCANGIA - special organs of some wood-inhabiting beetles and wood-wasps in which they carry their symbiotic ambrosia fungus.

MYCELIUM (pl. = MYCELIA) - collective term for hyphae; the vegetative thallus of a fungus excluding organs of sporulation or sclerotia.

MYCETOMES - pouches at the beginning of the midgut in anobiid beetles in which their endosymbiotic yeasts are stored.

MYCOBIONT - the fungal partner in a symbiotic relationship (mycorrhiza or lichen).

MYCOHERBICIDE - a prepartion of phytopathogenic fungi used to kill weeds.

MYCOINSECTICIDE - a preparation of entomopathogenic fungi used to kill insects.

MYCOLOGY - the study of fungi.

MYCOPARASITE - a fungus which attacks other fungi (sometimes called HYPERPARASITE).

MYCOPHAGOUS - eating fungi.

MYCORRHIZA - symbiotic relationship between a filamentous fungus and the roots of a plant; see ECTOMYCORRHIZA, ENDOMYCORRHIZA.

MYCOSES (sing. = MYCOSIS) - diseases of humans or animals caused by fungi (e.g., ringworm, histoplasmosis, coccidioidomycosis, athlete's foot).

MYCOTOXINS - fungal secondary metabolites which contaminate food and are poisonous to animals and humans.

MYXAMOEBA - amoeboid stage of Myxostelida, feeds phagotrophically and later becomes a plasmodium.

NANOMETRE - one-billionth of a metre: written as `nm'.

NECROSIS - death of cells or tissues.

NECROTROPH - an organism that kills tissues of living hosts by releasing toxins, then lives saprobically on the dead tissues.

NEMATODES - threadworms or roundworms; members of Phylum Nematoda, pseudocoelomate metazoa, 10,000 spp.; common in soil, decaying organic matter and as parasites of plants and animals.

NEPHROPATHY - kidney damage caused by mycotoxins.

NEUROTOXIN - a toxin which affects the nervous system.

nm - see NANOMETRE.

NOBLE ROT - a condition in which the mould Botrytis grows on overripe grapes. A rich, sweet, expensive wine is made in small quantities from such grapes (Sauternes, Trockenbeerenauslese, Botrytis-wine).

NOMENCLATURE - the naming of Fungi is governed by the International Code of Botanical Nomenclature as adopted by each International Botanical Congress; any proposals to change the Code are published, debated, and voted on at such Congresses. If more than one name has been applied to a fungus, the rules help decide which is the proper one. The rules also allow separate binomials for anamorph and holomorph.

NON-TARGET ORGANISMS - organisms found with or near those being treated with a chemical or biological control agent; it is important that these agents have as little effect as possible on non-target organisms.

NUCLEAR CAP - a mass of RNA and ribosomes near the nucleus in some zoospores.

NUCLEOLUS - organelle found in the nucleus of eukaryotic cells; composed mainly of ribosomal RNA in the process of being transcribed from from multiple copies of rRNA genes.

NUCLEOTIDE - a single unit of nucleic acid, composed of a phosphate, a five-carbon sugar (either ribose or deoxyribose), and a purine or a pyrimidine.

NUCLEUS - a specialized body within the eukaryotic cell bounded by a double membrane and containing the chromosomes.

NYSTATIN - an antifungal antibiotic derived from Streptomyces noursei, used to treat candidiasis.

OBLIGATE - invariably found in a particular situation; usually used in reference to organisms that must live in intimate association with a living host (cf. FACULTATIVE, OPPORTUNISTIC).

OCHRATOXINS - toxins of Aspergillus ochraceus, Penicillium verrucosum, etc.; causes kidney damage in sheep, cattle and pigs.

OESTROGENIC SYNDROME - a condition in which the mycotoxin, zearalenone, a steroid, causes severe sexual dysfunction in pigs (vaginal prolapse, shrivelled testes).

OLFACTORY - having to do with the sense of smell.

ONTJOM - an Indonesian fermented food, prepared from peanut press cake, which has been surface inoculated with the Monilia anamorph of Neurospora sitophila (Sordariales: Ascomycetes).

OOGAMY - a style of reproduction involving female gametes which are much larger than the male gametes, are non-motile, and may be called 'eggs.'  Oogamy is exhibited by the Oomycota and by the Monoblepharidales of the Chytridiomycota.

OOGONIUM (pl. = OOGONIA) - single-celled female gametangium giving rise to one or more `eggs'.

OOMYCOTA - Phylum of chromistan fungi with biflagellate, HETEROKONT zoospores; oogamous, with non-motile gametes; have cellulose walls, and diploid vegetative thalli; hence, Oomycetes.

OOSPHERE - unfertilized female gamete in oogamous fungi, esp. Oomycota.

OOSPORE - thick-walled resting spore developing from a fertilized egg of the Oomycetes.

OPERCULATE - describes sporangia (esp. some unitunicate asci), having a special lid or cap (operculum) that opens to permit spore discharge (cf. INOPERCULATE).

OPPORTUNISTIC - (relating to pathogens) fungi which are normally saprobic, but occasionally act as pathogens when condition unusually favourable for infection arise (cf. FACULTATIVE, OBLIGATE).

ORDER - taxonomic rank above Family, but below Class; suffix is -ales.

ORDERED TETRAD - the linear arrangement in the ascus of spores resulting from meiosis.

ORGANELLES - specialized sub-cellular structures which perform specific functions in eukaryotic cells, e.g., mitochondria, nucleoli, ribosomes: these are now believed to have been prokaryotic organisms which entered a symbiotic union with the ancestral eukaryotic cells.

ORGANOLEPTIC QUALITIES - attributes affecting the senses (taste, smell).

ORGANOMERCURIAL (RHgX) - organic fungicides incorporating mercury.

ORGANO-TIN (RSnX) - organic fungicides incorporating tin.

OSMOTIC PRESSURE - the potential pressure developed by a solution separated from pure water by a selectively permeable membrane that permits the passage of water, but not the dissolved substance.

OSMOTOLERANT - capable of growing under conditions of high osmotic pressure, as some yeasts and moulds on concentrated sugar solutions.

OSMOTROPHIC - acquiring food by absorption, as fungi do.

OSTIOLE - the opening at the top of many fungal fruit bodies (perithecia, pycnidia, puffball basidiomata) through which spores escape or are expelled.

OXIDATIVE PHOSPHORYLATION - the formation of ATP from ADP and inorganic phosphate that takes place in the electron transport chain of the mitochondrion.

PAINT FUNGI - wood-inhabiting basidiomycetes with thin, spread out, indefinite basidiomata; many Corticiaceae and Thelephoraceae: Aphyllophorales.

PALAEOZOIC - the geological era covering the period from 600-225 million years before present (m.y.b.p.); includes the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods.

PAPILLA - a nipple-like extension, as on the auxiliary cells of some VAM fungi.

PARAPHYSIS (pl. = PARAPHYSES) - sterile hyphae growing up between the asci in the hymenium of many ascomycetes.

PARASEXUALITY - genetic recombination during the mitotic cycle, best known in conidial fungi (ascomycetous anamorphs, such as Aspergillus).

PARASITIC - deriving nourishment from another living organism (the host) (cf. NECROTROPHIC, SAPROBIC).

PARENCHYMATOUS - describes tissues or thalli made up of thin-walled, apparently randomly arranged cells, packed tightly together and thus usually polygonal.

PARENTHESOME - a perforated dome of membrane that covers each end of a dolipore.

PARTIAL VEIL - membrane enclosing gill cavity during development in some agarics; after rupture, it remains as a ring or annulus on the stipe (cf. UNIVERSAL VEIL).

PATHOGEN - an organism that causes disease.

PATULIN - a mycotoxin from Aspergillus clavatus, Penicillium patulum, P. expansum; antibacterial and antifungal; toxic to plants and animals (carcinogenic to mice) and the cause of neurotoxicosis in cattle.

PCR - polymerase chain reaction, a way of replicating a small amount of DNA over and over again until a usable amount has been produced.

PEACH LEAF CURL - a leaf hypertrophy caused by Taphrina deformans (Taphrinales: Ascomycetes).

PENICILLIN - an antibacterial antibiotic produced by Penicillium spp. (Hyphomycetes). 

PENITREM A - a mycotoxin produced by various Penicillium spp., incl. P. cyclopium, which affects the nervous system, causing tremors; see NEUROTOXIN, TREMORGEN.

PERCURRENT - growing on through the scar left by release of a previous terminal spore; see ANNELLIDIC.

PERIDIOLES - the `eggs' in bird's-nest fungi (Nidulariales); disc-shaped bodies within which the basidiospores are borne, and which are splashed out of the cup-shaped basidioma by raindrops.

PERIDIUM (pl. = PERIDIA) - outer covering of various sporangia in the Zygomycetes, and of the gleba in many Gasteromycetes.

PERITHECIAL ASCOMA - walled ascoma usually having an ostiole through which spores can be expelled at maturity; the asci are arranged in an hymenium; characteristic of many ascomycetes with unitunicate-inoperculate asci.


PERMEASE - transport protein or carrier molecule that assists in the movement of substances across cellular membranes; not permanently altered in the process.

pH (potential Hydrogen) - a symbol for hydrogen ion concentration in a solution; pH values run from 0 to 14 on a logarithmic scale, the lower the value, the greater the concentration of hydrogen ions, and the more acidic a solution is; pH 7 is `neutral', pH less than 7 is acidic, pH greater than 7 is alkaline or basic.

PHAGOTROPHIC - feeding by ingestion; engulfing food (no fungus does this).

PHENOTYPE - the physical expression of the genotype.

PHEROMONE - a sexual attractant liberated in minute quantities, yet capable of inducing chemotaxis of the `target' at a considerable distance.

PHIALIDE - a conidiogenous cell which produces a basipetal succession of blastic conidia from an open end without any change in the length of the cell.

PHIALIDIC - describes conidia produced by a phialide.

PHLOEM - food-conducting tissue in vascular plants; basically composed of sieve elements, various kinds of parenchyma cells, fibres and sclereids.


PHOSPHORYLATION - a reaction in which phosphate is added to a compound, e.g., the formation of ATP from ADP and inorganic phosphate.

PHOTOSYNTHETIC - having the ability to convert light energy to chemical energy; able to produce carbohydrates from carbon dioxide in the presence of chlorophyll.

PHOTOTROPISM - growth toward a light source, as in many dung-inhabiting fungi, e.g., Pilobolus (Zygomycetes), Sordaria, Ascobolus (Ascomycetes).

PHRAGMOBASIDIOMYCETES - Basidiomycetes in which the basidia are subdivided by primary septa (Orders: Tremellales, Auriculariales) (cf. HOLOBASIDIOMYCETES, TELIOMYCETES).

PHRAGMOBASIDIUM (pl. = PHRAGMOBASIDIA) - a basidium with three transverse septa, characteristic of the Phragmobasidiomycetes (q.v.) and also the Teliomycetes.

PHRAGMOSPORE - a spore which has two or more transverse septa; septa appearing like the rungs of a ladder.

PHTHALIMIDES - the protectant fungicides: Captan, Captafol/Difolatan, Folpet/Phaltan.

PHYCOBIONT - the algal partner in a symbiotic relationship, as in a lichen.

PHYLOGENETIC - classification of organisms designed to reflect the sequence in which they evolved, and their genetic relationships.

PHYLOGENY - evolutionary relationships among organisms; developmental history of a group of organisms.

PHYLUM (pl. = PHYLA) - a taxon above Class, but below Kingdom. There are five Phyla of fungi: Dikaryomycota, Zygomycota and Chytridiomycota (Eumycotan), Oomycota and Hyphochytriomycota (Chromistan).

PHYSIOLOGY - the study of the activities and processes of living organisms.

PHYTOALEXIN - a metabolite, produced by a plant in response to infection by a pathogen (or by an abiotic factor), which inhibits the pathogen.

PHYTOBIONT - the plant partner in a mutualistic symbiosis, e.g. a mycorrhiza.

PILEIPELLIS - the superficial layer of cells covering the upper side of the cap of an agaric.

PILEUS - the spore-bearing cap or head of a mushroom or other large fungal fructification.

PLANKTON - free-floating aquatic organisms; usually microscopic; form the base of all aquatic food webs (including that of the oceans).

PLASMALEMMA - or plasma membrane; outer boundary of the protoplast, next to the cell wall; consists of a single membrane; also called cell membrane and ectoplast.

PLASMID - a relatively small, circular fragment of DNA which can exist free in the cytoplasm and can be used as a vector in gene cloning.

PLASMODIUM - a naked, multinucleate, phagotrophic, amoeboid thallus, as in Myxostelida.

PLASMOGAMY - fusion or mixing of the cytoplasm of two cells; follows anastomosis and often precedes karyogamy.

PLASTIDS - organelles in the cells of certain groups of eukaryotes manufacture and store food; plastids are bounded by a double membrane, e.g., chloroplasts.

PODETIA - upright, cylindrical structures in lichens (esp. Cladonia) which often bear apothecial ascomata at their apex.

POLYMER - a compound made by linking many identical smaller molecules (monomers).

POLYPEPTIDES - organic compounds made up of amino-acids linked by peptide bonds.

POLYPHYLETIC - genetically heterogeneous, because of having arisen from different ancestral groups.

POLYPORES - the shelf- or bracket-fungi; hymenomycetes living on dead (or sometimes living) trees and often producing perennial basidiomata in which the hymenium lines annual layers of corky, vertically oriented tubes.

POLYSACCHARIDE - a polymer made up of many linked monosaccharides, e.g., cellulose, a polymer of glucose.

POWDERY MILDEWS - plant diseases caused by obligately parasitic fungi (Erysiphales: Ascomycetes).

ppb - parts per billion; a measure of concentration.

ppm - parts per million; a measure of concentration.

PRECAMBRIAN - geological era from the earliest days of the earth until 600 million years ago, at the end of which the earth's atmosphere is believed to have attained a level of oxygen capable of supporting multicellular, eukaryotic organisms.

PRECURSOR - a substance that precedes and is the source of another substance.

PREDACEOUS FUNGI - specialized fungi of several phyla which trap or infect nematodes, rotifers, collembola, amoebae, tardigrades, etc., exploiting them either as principal diet or as a nitrogen supplement.

PREDACEOUS - preying upon other organisms, as in the nematode-exploiting fungi.

PRIMARY HOST - the principal host of heteroecious rust fungi, which bears the sexual phase (the teliospores); see ALTERNATE HOST.


PRIMARY PRODUCTION - elaboration of complex, energy-rich organic compounds by photosynthetic organisms. Fungi and animals are ultimately totally dependent on this process.

PRIMORDIUM - the first stage of development of an organ or sporoma.

PROKARYOTIC - lacking a membrane-bound nucleus and paired chromosomes; also lacking cytoplasmic organelles such as ribosomes, mitochondria and golgi apparatus: describes the bacteria and the cyanobacteria (cf. EUKARYOTIC).

PROLAPSE - a condition in which an organ becomes displaced (see oestrogenic syndrome in pigs).

PROMOTER - a nucleotide sequence in a gene to which RNA polymerase attaches in order to begin transcription of mRNA.

PROTEASE - an enzyme that digests protein.

PROTECTANT - a fungicide that can give protection from a pathogen by killing its spores or germ tubes while they are still outside the host, but cannot cure an existing infection (cf. ERADICANT).

PROTEIN - a long chain of amino acids (usually more than 100) joined by peptide bonds.

PROTOPLASM - fluid living content of a cell, the cytoplasm and nucleoplasm.

PROTOPLAST - the membrane-bounded living contents of a cell from which the wall has been removed enzymically to facilitate transformation.

PROTOTROPH - the wild type, as found in nature, which can synthesize a substance which a corresponding auxotroph (q.v.) mutant cannot.

PROTOTUNICATE - describes a kind of ascus that is basically unitunicate, but whose wall lyses at or before maturity; such asci may develop in a hymenium or may be distributed randomly in the interior of the ascoma.

PR TOXIN - a toxin produced by Penicillium roquefortii fortunately not during the ripening of blue cheeses.

PSEUDOPARAPHYSES - specialized hyphae found in some bitunicate ascomycetes; they grow down from the roof of the pseudothecial ascoma and dissolve a space for the developing asci.

PSEUDOPARENCHYMATOUS - describes `tissue' made up of very densely packed fungal hyphae which in mass have come to resemble a perithecial ascoma.

PSEUDOTHECIAL ASCOMA - ascoma containing bitunicate asci; often resembling a perithecial ascoma, though developing differently.


PSILOCIN and PSILOCYBIN - hallucinogenic indoles found in many species of Psilocybe, and some species of Panaeolus, Gymnopilus and Conocybe.

PSYCHEDELIC - mind-altering, hallucinogenic, psychoactive.

PSYCHROTOLERANT - growing at temperatures below 10C (optimum temp. below 20C).

PUFFBALL - a gasteromycete basidioma in which the basidiospore mass (gleba) is enclosed by a papery peridium at maturity; an ostiole allows compression or wind suction to disperse basidiospores in the Lycoperdales and Tulostomatales; the basidiomata of the Sclerodermales have no ostiole.

PUFFING - a phenomenon in which thousands of asci in an apothecial ascoma discharge their ascospores simultaneously, producing a visible cloud of spores.

PULLEYWHEEL OCCLUSION - the structure blocking the septal pore in hyphae of the rust fungi (Uredinales).


PYCNIDIAL CONIDIOMA - a flask-shaped sporoma produced by coelomycetous anamorphs.

PYRENOLICHENS - lichens in which the mycobiont produces perithecial or pseudothecial ascomata.

RADIOIMMUNOASSAY - an immunoassay in which radioactive tracers are introduced into the substance to be analyzed.

RAPD - random amplified polymorphic DNA. PCR is used with short primers to amplify parts of target DNA that can then be compared in gel electrophoresis. Useful in finding species-specific patterns and in dealing with very small amounts of material.

RECEPTACLE - the head of the stinkhorns (Phallales), bearing the slimy gleba.

RECEPTIVE HYPHAE - special hyphae arising from spermagonia of rust fungi; the spermatia from other spermagonia fuse with them and initiate the dikaryon.

RECESSIVE - describes a gene whose phenotypic expression is masked by a dominant allele.

RECOMBINANT DNA - DNA of two different species spliced together in the laboratory (see CLONING).


REINDEER 'MOSS' - the fruticose lichen, Cladonia rangiferina, and similar species.

RELATIVE HUMIDITY (RH) - an index of water content, expressed as a percentage of the saturated value.

RESTRICTION ENDONUCLEASE - an enzyme used to cleave DNA at specific base pairs.

RESUPINATE - describes basidiomata that lie flat or spread out in a thin layer on the substrate, with a superficial hymenium: `paint fungi' of families Thelephoraceae, Corticiaceae (Aphyllophorales: Holobasidiomycetes).

RETINA - a light-sensitive area, as in the subsporangial vesicle of Pilobolus.

RETROGRESSIVE - a mode of blastic conidiogenesis in which the short cylindrical segments of the conidiogenous cell differentiate into conidia; the conidiogenous cells becomes shorter during conidiation.

RFLP - Restriction Fragment Length Polymorphism. DNA is cut with one or more restriction enzymes, and the resulting fragments are separated using gel electrophoresis (the smaller fragments - those with fewer base pairs - travelling further along the gel) which produces specific banding patterns called profiles.

RHEXOLYTIC - secession of conidia involving the circumscissile rupture or breakdown of the longitudinal wall of the cell below the conidium (cf. SCHIZOLYTIC).

RHIZOIDS - very narrow, branched, usually enucleate, assimilative filaments found in the microscopic thalli of Chytridiomycota, etc. Rooting branches found at the base of some sporangiophores and conidiophores.

RHIZOMORPH - a root-like, macroscopic aggregation of hyphae with a cortex of dark cells and a central core of long, unpigmented cells; functions in translocation of food; characteristic of Armillaria mellea.

RHIZOMYCELIUM - extensive nucleate rhizoidal system found in some chytrids; possibly the precursor of true hyphae.

RIBONUCLEIC ACID (RNA) - type of nucleic acid formed on chromosomal DNA and involved in protein synthesis; composed of chains of phosphate, sugar molecules (ribose), and purines (adenine, guanine) and pyrimidines (cytosine, uracil).

RIBOSOMES - organelles which are the site of protein synthesis.


RINGWORM - superficial mycoses caused by keratinophilic Hyphomycetes; see DERMATOPHYTES, TINEA.

RNA - see RIBONUCLEIC ACID; tRNA = transfer RNA; mRNA = messenger RNA; rRNA = ribosomal RNA.

ROCK TRIPE - rock-inhabiting lichens of the genus Umbilicaria.

ROOTLET - part of the cytoskeleton supporting the base of a flagellum.

RUMPOSOME - honeycomb-like organelle of unknown function in Chytridiomycete zoospores.

RUSTS - plant diseases caused by obligately parasitic fungi (most are Uredinales: Teliomycetes, but the so-called white rust of brassicaceous plants is caused by an oomycete).

SAPROBE - a heterotrophic organism that derives food from dead organisms, or from organic substances liberated by living ones (cf. PARASITE, NECROTROPH, SYMBIONT).

SCHIZOLYTIC - secession of conidia involving a splitting of the delimiting septum so that one half of the crosswall becomes the base of the seceding conidium and the other half covers the apex of the conidiogenous cells (cf. RHEXOLYTIC).

SCLEROTIUM (pl. = SCLEROTIA) - a firm, frequently rounded, mass of hyphae with or without the addition of host tissue or soil, normally having no spores in or on it (cf. BULBIL, STROMA); a sclerotium may give rise to a fruit body, or mycelium.

SCOLECOSPORES - spores which are very long and thin (length/width ratio more than 15:1).



SEM - scanning electron microscope.  Objects are coated with a thin layer of a metal in a vacuum, and examined in an electron beam.

SEPTA (sing. = SEPTUM) - bulkheads occurring at regular intervals in most eumycotan fungi; they strengthen hypha and define the compartments, but are perforate and in many cases allow passage of cytoplasm and nuclei.

SEQUESTRATE - describes fungal fruit bodies which have evolved from exposed hymenia and forcibly discharged spores to a closed or even hypogeous habit in which the spores are retained in the fruit body until it decays or is eaten by an animal vector. Many sequestrate taxa can be clearly recognized a s being derived from specific spore-shooting ancestors, e.g. Rhizopogon from Suillus (Boletaceae).

SESSILE - not stalked; sitting directly on substrate.

SETAE - stiff, often pointed, erect hyphae which protrude from a fertile layer or fruiting body and may have a protective function.

SEXUAL REPRODUCTION - the fusion of gametes followed by meiosis and recombination at some point in the life cycle.


SHII-TAKE - Lentinus edodes; a domesticated edible agaric used in Japanese and Chinese cuisine; the fungus is grown on logs of Fagaceae (oak, beech).

SHORT CELLS - cells of a dimorphic plant root exodermis which remain unsuberized long enough to permit ingress by VAM fungi.

SHOT-HOLE DISEASE - a leaf disease in which the spread of infection is limited when the host sheds the infected area of the leaf.

SHOYU (SOY SAUCE) - an Oriental sauce of soybeans and wheat fermented by Aspergillus, yeasts, and bacteria.

SIRENIN - a hormone secreted by female gamete of Allomyces which attracts male gametes.

SKELETAL HYPHAE - thick-walled, little branched, non-septate hyphae found in dimitic and trimitic basidiomata (cf. BINDING, GENERATIVE hyphae).

SLAFRAMINE - a mycotoxin produced by Rhizoctonia leguminicola; causing excessive salivation or slobbering in ruminants feeding on certain fungus infected legume forage crops.

SMUTS - plant diseases, often specific to higher plant sex organs, caused by the Ustilaginales (Teliomycetes).

SOMATIC - pertaining to the vegetative or assimilative body of an organism.

SOREDIA (sing. = SOREDIUM) - lichen propagules -- small aggregations of fungal hyphae around algal cells; formed by the break up of a thallus.

SOROCARP - the fruiting body of the Dictyostelida (cellular slime moulds).

SORUS - a simple fruiting structure produced by rust and smut fungi; an aggregation of spore-bearing cells bursting through the host epidermis.

sp.- abbreviation for one species.

spp. - abbreviation for more than one species.

SPECIES - the lowest-ranking taxon normally used (though subspecies, variety and race are subspecific taxa); comprises individuals very similar in all major respects; often used for organisms that are normally capable of interbreeding; among anamorphic fungi has a mainly morphological/developmental connotation. The name of a species is called a binomial or binominal, and has two parts, a generic name which is capitalized, followed by a species epithet. Both words are italicized.

SPERMAGONIUM - flask-shaped sporoma producing spermatia; found in rust fungi.

SPERMATIUM (pl. = SPERMATIA) - non-motile male gamete, as in the rust fungi.

SPHAEROCYSTS - large, turgid, thin-walled cells, found clustered in the tissues of Russula and Lactarius (Agaricales), and accounting for the peculiar brittle texture of their flesh.

SPINDLE FIBRES - a group of microtubules that extend from the centromere of chromosomes to the poles of the spindle or from pole to pole in a dividing cell.

SPORANGIOLE - a reduced sporangium containing only one or a few spores; characteristic of some zygomycetous anamorphs.

SPORANGIOPHORE - specialized hyphal branch bearing one or more sporangia in Oomycetes, Zygomycetes, etc.

SPORANGIUM - a specialized cell within which a spore or spores are developed. See MITOSPORANGIUM, MEIOSPORANGIUM, SPORANGIOLE, ZOOSPORANGIUM.

SPORE - specialized microscopic propagule, usually an agent of dispersal, in fungi, cryptogamic plants, many protozoa, chromista and bacteria: capable of developing into an adult without fusion with another cell. In fungi may be unicellular or composed of two to many cells.

SPORE PRINT - a visible deposit of basidiospores obtained by allowing an agaric to drop spores onto white paper overnight; the colour of this deposit is an important aid to identification.

SPORIDESMIN - hepatotoxic mycotoxin formed by Pithomyces, causes facial eczema in sheep.

SPORIFEROUS VESICLE - a thin-walled accessory cell distal to, or behind and to one side of, the chlamydospore of some VAM fungi.

SPOROCARPS - discrete aggregation of spores of some arbuscular-mycorrhizal fungi formed in or on the soil.

SPORODOCHIAL CONIDIOMA (SPORODOCHIUM) - a cushion-like sporoma produced by some hyphomycetous anamorphs.

SPOROMA (pl. = SPOROMATA) - any multicellular structure specially developed to produce spores.

SPOROTRICHOSIS - a lymphatic mycosis caused by Sporothrix schenckii (Hyphomycetes).

SPORULATION - the production of spores.

SQUAMULOSE - describes lichen thalli which consist of small scales.

STACHYBOTRYOTOXIN - a mycotoxin produced by the hyphomycete, Stachybotrys, growing on hay; implicated in serious poisoning of horses.

STALING - accumulation of metabolites which slow or stop growth of the organism which produces them.

STAUROSPORES - spores with three to many radiating extensions.

STELE - the central cylinder of conductive tissue in roots.

STERIGMA (pl. = STERIGMATA) - a short apical outgrowth of a basidium, with a minute, pointed extremity on which a basidiospore is produced and from which it is forcibly discharged. (N.B.: sometimes incorrectly applied to small phialides and other peg-like structures on which spores are borne).

STERILIZATION - the process whereby all microorganisms and their propagules are killed by exposure to heat (see AUTOCLAVING), radiation, or chemicals, or removed by filtration.

STEROL-INHIBITORS - systemic but non-selective fungicides, e.g., bitertanol (Bayor); triadimefon (Bayleton); fenarimol (Rubigan, Bloc); triforine (Funginox, Saprol); etaconazole (Vangard); triarimol (Trimidal); prochloraz (Sportak); fenapanil which inhibit sterol formation, and thus membrane formation.

STINKHORN - basidioma of some members of the order Phallales (Gasteromycetes).

STIPE - a stalk which lacks true vascular tissue, as in mushrooms.

STIPITATE - stalked.

STOMATE - a minute, intercellular fissure in the epidermis, surrounded by guard cells.

STRIATED DISC - flattened, fan-shaped assemblage of microtubules and fibrils extending from the side of the kinetosome in zoospores of the Monoblepharidales.

STROMA (pl. = STROMATA) - mass of fungal tissue within which or from which perithecial or other fructifications are formed (cf. SCLEROTIUM, BULBIL).

SUBERIN - fatty material found in plants in the cell walls of cork tissue, of the endodermis (the Casparian band), and of the exodermis; its presence can prevent fungal penetration.

SUBICULUM - a wool- or crust-like growth of mycelium under fruit bodies.

SUBPHYLUM - taxon above Class but below Phylum; suffix is -mycotina, e.g. Ascomycotina, Basidiomycotina

SUBSTRATE - (1) the food of a fungus; (2) substance acted on by an enzyme; (3) the material from which a fungus is fruiting - e.g. polypores mostly occur on wood.

SUCROSE - a disaccharide, C12H22O11, consisting of glucose and fructose monomers.


SURFACTANT - an agent which reduces the surface tension of a liquid, e.g., detergents.

SUSPENSORS - the empty walls of the two gametangia which remain attached to maturing zygosporangia in the Zygomycota.


SYMBIOSIS - a state of intimate association or living together; the relationship benefits both partners in MUTUALISTIC symbioses, or one partner at the expense of the other in PARASITISM, or may be neutral, as in COMMENSALISM.

SYMPLASTIC - entering living cells (cf. APOPLASTIC).

SYMPODIAL - describes blastic conidia formed on a conidiogenous cell by the growth of a succession of apices, each originating below and to one side of the last. The conidiogenous cell usually becomes longer, but in some cases becomes inflated, as a result of repeated spore formation. See Chapter 4a.

SYNANAMORPH - one of two or more different anamorphs which develop simultaneously, or are otherwise known to be associated with a single teleomorph.

SYNCHRONOUS - describes blastic conidia initiated simultaneously in a cluster or on a specialized cell.

SYNERGISM - a condition in which two substances, e.g. fungicides, when used together, have a greater effect than either could produce alone.

SYNNEMATAL CONIDIOMA (SYNNEMA) - the sporoma of some hyphomycetes, in which many conidiophores are aggregated into a column.

SYSTEMIC - describes a fungicide or pathogen which enters and becomes widely distributed within the body of a plant or animal.

TAKE-ALL - a cereal disease caused by Gaeumannomyces graminis (Diaporthales: Ascomycetes).

TARGET ORGANISM - the organism against which a treatment is directed (cf. NON-TARGET ORGANISM).

TAXA (sing. = TAXON) - groupings of organisms made for systematic purposes: range in rank from species to Kingdom.

TAXONOMY - the classification of organisms on the basis of their evolutionary relationship; see CLASSIFICATION.

TELEOMORPH - the sexual manifestation of a fungus; unknown in many taxa (cf. ANAMORPH, HOLOMORPH).

TELIOMYCETES - Class of basidiomycetes including the orders Uredinales and Ustilaginales. Their teleomorphs consist of teliospores from which basidia develop.

TELIOSPORES - thick-walled resting spores that essentially constitute the teleomorph of the Uredinales and Ustilaginales; karyogamy takes place in them, and they germinate to produce a basidium.

TEMPEH - an Oriental food made by fermenting soybeans with Rhizopus oligosporus.

TEONANACATL - `the Flesh of the Gods,' magic mushrooms used in Central American curing and divining ceremonies.

TERATOGENIC - causing abnormalities of growth of a fetus.

TERTIARY - the geological era covering the period from 65-1 million years ago: include the Palaeocene, Eocene, Oligocene, Miocene, and Pliocene periods; if the last million years, the Pleistocene, is included, this 65 million year span is often called the Cenozoic era.

TETRAPOLAR - describes a system of heterothallism in which sexual compatibility is controlled by many alleles, all occurring at 2 loci (cf. BIPOLAR).

TETRARADIATE - describes the staurospores of some stream-inhabiting fungi; the four (sometimes more) arms ensure a stable three-point landing on the substrate.

THALLIC - one of two basic modes of conidium development; if there is any enlargement of the conidium initial, it occurs only after the initial has been cut off by a septum; derived from conversion of pre-existing hyphal elements (cf. BLASTIC).

THALLUS (pl. = THALLI) - the usually ill-defined `body' of a fungus.

THERMOLABILE - tending to break down when heated.

THERMOTOLERANT - capable of growing at high temperatures (up to 60C, opt. 40-50C) (cf. PSYCHROTOLERANT).

THRUSH - a yeast infection of the mouth and throat, esp. in children, caused by Candida albicans.

TINEA - a superficial infection caused by dermatophytes (q.v.).

TINSEL FLAGELLUM - a flagellum with lateral flimmers or mastigonemes (cf. WHIPLASH flagellum).

TISSUE - a group of similar cells organized into a structural and functional unit.

TOADSTOOL - see MUSHROOM, AGARIC; toadstool is a confused term -- it is assumed to refer to poisonous agarics, but many so-called toadstools are harmless; use `agaric' instead, and join the cognoscenti.

TOOTH FUNGI - members of the family Hydnaceae (Aphyllophorales: Basidiomycetes) in which the hymenium covers downwardly directed teeth.

TOXIGENIC - producing toxins.

TRACE ELEMENTS - elements essential for growth, but required only in minute amounts.

TRAMA - the sterile tissue of a basidioma, esp. that in the centre of the gills.

TRANSCRIPTION - the enzyme-catalyzed assembly of an RNA molecule along a strand of DNA.

TRANSFER SPORES - (of rust fungi) see AECIOSPORES.

TRANSFORMATION - a genetic change produced by the introduction of foreign DNA.

TRANSLATION - the assembly of a protein on a ribosome, amino-acids being brought to the site by tRNA (transfer RNA) and their order of assembly being specified by mRNA (messenger RNA).

TRANSLOCATION - movement of nutrients or other substances within an organism.

TREHALOSE - a crystalline sugar, C12H22O11, characteristically found in fungi.

TREMORGEN - a mycotoxin inducing a neurotoxicosis (tremor) in man and other mammals; a NEUROTOXIN.


TRICHOGYNE - an extension of the ascogonium (in some Ascomycetes) which facilitates fertilization.

TRICHOMYCETES - an inconspicuous Class of Zygomycota, found attached to the gut walls of insects.

TRICHOTHECENES - mycotoxins (scirpenes) of Fusarium tricinctum, F. sporotrichioides, F. poae, and Trichothecium (Hyphomycetes).

TRIMITIC - describes basidiomata constructed of three different types of hyphae, generative, skeletal and binding.

TRUFFLE - an edible hypogeous ascoma of the genus Tuber (Pezizales: Ascomycetes). Can also be applied to the basidiomata of many hypogeous basidiomycetes, though these are not generally edible.

TUNING-FORK BASIDIA - the typical basidia of the order Dacrymycetales (Holobasidiomycetes), which have only two spore-bearing extensions.

T-2 TOXIN - a mycotoxin of the trichothecene group, produced by several Fusarium spp.; the cause of alimentary toxic aleukia.

UNITUNICATE - describes a type of ascus with only one distinct, functional wall layer (cf. BITUNICATE).

UNIVERSAL VEIL - membrane totally enclosing some young agaric basidiomata (as in Amanita); after rupture it remains as the volva around base of the stipe, and often also as scales on the cap (cf. PARTIAL VEIL).

UREDINIOSPORES - the dikaryotic `summer spores' of Uredinales, which spread the fungus from plant to plant of the primary host during the growing season.

VAM - vesicular arbuscular mycorrhizal (endomycorrhizal) - more correctly AM or arbuscular mycorrhizal, since not all fungi producing this kind of mycorrhiza have vesicles.

VASOCONSTRICTION - constriction of blood vessels.

VECTOR - an organism which consciously or unconsciously aids in the dispersal of another, e.g., dipteran flies are vectors for stinkhorns.

VEGETABLE CATEPILLAR - a mummified lepidopteran larva from which arises the stromatic teleomorph of a species of Cordyceps (Clavicipitales: Ascomycetes).

VEIL - see ANNULUS (partial veil), VOLVA (universal veil).

VESICLE - (1) small, intracellular, membrane-bounded sac in which substances are transported or stored; (2) swollen, lipid-filled cells produced inside plant roots by most endomycorrhizal fungi (sometimes called intramatrical spores).

VESICULAR-ARBUSCULAR MYCORRHIZAS - endomycorrhizas; plant roots colonized by mutualistic fungi of the Glomales (some of which do not produce vesicles, suggesting that these mycorrhizas should simply be described as ARBUSCULAR MYCORRHIZAS).

VIRULENCE - the degree or measure of pathogenicity.

VOLVA - a sheath around the base of the stipe in some agarics, esp. the poisonous Amanita; remains of the universal veil.

VOMITOXIN - 4-Deoxynivalenol, a trichothecene; a mycotoxin produced by Fusarium graminearum (Hyphomycetes); esp. in barley and winter wheat; has an emetic effect livestock.

WATER ACTIVITY (aw) - expresses the available water in a substrate as a decimal fraction of the amount present when the substrate is in equilibrium with a saturated atmosphere (an equilibrium relative humidity of 70% around the substrate means that the substrate has a water activity of 0.70).

WATER MOULDS - members of the Order Saprolegniales (Oomycetes).

WHIPLASH FLAGELLUM - a flagellum with a smooth shaft (cf. TINSEL flegellum)

WHITE ROT - a wood rot produced by basidiomycetes that can degrade both cellulose and lignin.

WHITE RUST - disease of crucifers caused by Albuginaceae (Peronosporales: Oomycota).

WILT - a plant disease, caused by species of Verticillium and Fusarium (Hyphomycetes), characterized by loss of turgidity and collapse of leaves.

WINTER SPORES - (of rust fungi) see TELIOSPORES.

WITCHES' BROOMS - massed outgrowths (proliferations) of the branches of woody plants caused by mites, viruses, etc., and fungi, esp. rust fungi.

WORONIN BODIES - two small spherical objects that sit, one on each side, near the pore of the ascomycete septum.

XEROTOLERANT - able to grow under dry conditions.

XYLEM - lignified water-conducting tissue in vascular plants.

XYLOSE - a pentose sugar, C5H10O5, found in the cell walls of basidiomycetes.

YEASTS - fungi which in many cases are unicellular, though some produce hyphae; most yeasts are anamorphs; their cells are conidia, and they multiply by various kinds of conidiogenesis. Some can produce asci, some can form basidia, and some appear to be anamorphic holomorphs -- entirely asexual.

ZEARALENONE - a mycotoxin produced by Fusarium graminearum (teleomorph in Gibberella zeae); the cause of oestrogenic syndrome (vulvovaginitis and infertility) in pigs.

ZOOSPORANGIA (sing. = ZOOSPORANGIUM) - sporangia within which zoospores (flagellate spores) develop.

ZOOSPORES - flagellate, motile, asexual spores released by chromistan and some eumycotan fungi.

ZYGOMYCETES - one of the two classes of Zygomycota (see also TRICHOMYCETES)

ZYGOMYCOTA - Phylum of true fungi; two Classes - (1) Zygomycetes: fast-growing, terrestrial, largely saprobic fungi with no motile cells; produce zygosporangia by fusion of usually similar gametangia; also asexual sporangia containing 1 to many non-motile spores, and borne on simple to complex sporangiophores. (2) Trichomycetes: apparently commensal fungi found attached to the gut wall of arthropods.

ZYGOSPORANGIUM - the teleomorph of the Zygomycetes; a usually thick-walled, often ornamented, multinucleate resting sporangium formed following anastomosis of gametangia arising from compatible mycelia (in heterothallic species) or from the same mycelium (in homothallic species).

ZYGOTE - a diploid cell or protoplast formed as a result of fusion of two haploid nuclei during sexual reproduction; zygotes often become resting spores, but ultimately germinate to produce either a diploid generation (very few fungi, many algae, all higher plants) or undergo meiosis and, following this genetic recombination, re-establish the haploid phase.