CS156 Mycology Lectures 1-6 – Vocabulary Review

A comprehensive set of core vocabulary terms and definitions derived from CS156 Mycology Lectures 1–6, covering fungal structure, reproduction, nutrition, taxonomy, and ecological importance.

Mycology

The scientific study of fungi.

Fungus (pl. Fungi)

Eukaryotic, spore-producing, achlorophyllous organism with absorptive nutrition and cell walls typically containing chitin.

Hypha (pl. Hyphae)

Filamentous, tubular fungal cell that forms the basic structural unit of most fungi.

Mycelium

A mass of branching hyphae that constitutes the vegetative body of a fungus.

Yeast

Unicellular, non-filamentous fungus that reproduces mainly by budding or fission.

Dimorphic fungus

Species able to grow as hyphae under some conditions and as yeasts under others.

Chitin

Long-chain polymer of N-acetylglucosamine that is the primary structural component of most fungal cell walls.

β-Glucan

Cell-wall polysaccharide composed of glucose units; abundant in many fungi.

Ergosterol

Sterol component of fungal cell membranes; fungal analogue of cholesterol.

Septate hypha

Hyphal filament subdivided by cross walls (septa) with pores for cytoplasmic continuity.

Coenocytic (aseptate) hypha

Hypha lacking regular cross walls, containing many nuclei within a continuous cytoplasm.

Clamp connection

Hook-like hyphal outgrowth in Basidiomycota that helps maintain dikaryotic state during cell division.

Dikaryon

Hyphal cell containing two genetically distinct haploid nuclei.

Monokaryon

Hyphal cell containing a single nucleus.

Conidium (pl. Conidia)

Non-motile asexual spore formed on a conidiophore.

Conidiophore

Specialized hypha that bears conidia.

Macroconidium

Relatively large, often multicellular conidium.

Microconidium

Small, usually unicellular conidium.

Sporangiospore

Asexual spore produced inside a sporangium.

Sporangium

Sac-like structure containing sporangiospores; borne on a sporangiophore.

Zoospore

Motile sporangiospore with one or two flagella.

Aplanospore

Non-motile sporangiospore.

Tinsel flagellum

Anterior, feathery flagellum bearing mastigonemes; characteristic of heterokont zoospores.

Whiplash flagellum

Smooth posterior flagellum that propels the zoospore.

Appressorium

Specialized, flattened hyphal cell that adheres to host surfaces and initiates penetration.

Penetration peg

Narrow hyphal outgrowth emerging from an appressorium to enter host tissue.

Haustorium

Absorptive hyphal structure formed inside host cells to obtain nutrients.

Sclerotium (pl. Sclerotia)

Hard, melanized resting body composed of compact mycelium; enables long-term survival.

Rhizomorph

Root-like, dense aggregation of hyphae functioning in nutrient translocation and survival.

Plectenchyma

General term for fungal tissue formed by aggregated hyphae.

Prosenchyma

Loosely woven plectenchyma in which individual hyphae remain recognizable.

Pseudoparenchyma

Compact plectenchyma resembling plant parenchyma; hyphal individuality lost.

Aerial mycelium

Hyphae that project above substrate surface and often bear reproductive structures.

Vegetative mycelium

Substrate-penetrating hyphae involved in nutrient absorption.

Fertile mycelium

Aerial hyphae that produce spores (conidia or sporangia).

Dematiaceous (phaeoid) fungi

Fungi whose hyphae contain melanin, producing dark-coloured colonies.

Hyaline hyphae

Colourless, non-pigmented fungal filaments.

Teleomorph

Sexual (meiotic) state of a fungus.

Anamorph

Asexual (mitotic) state of a fungus.

Holomorph

Whole fungus, encompassing all sexual, asexual, and vegetative states.

Hyphal fragmentation

Asexual reproduction where hypha breaks into pieces that grow into new individuals.

Arthrospore

Asexual spore produced by segmentation and separation of hyphal cells.

Budding

Asexual reproduction where a new cell develops from a small outgrowth of the parent cell.

Fission

Division of a cell into two equal daughter cells by constriction and formation of a new wall.

Chlamydospore

Thick-walled asexual resting spore formed within or at ends of hyphae.

Blastic conidiogenesis

Method where conidium enlarges before being cut off by a septum.

Thallic conidiogenesis

Method where a hyphal segment is first delimited by a septum and then develops into a conidium.

Catenulate conidia

Conidia borne in chains.

Acropetal chain

Conidial chain where youngest spore is at the tip (away from conidiogenous cell).

Basipetal chain

Conidial chain where youngest spore is nearest the conidiogenous cell.

Sporodochium

Cushion-like mass of conidiophores producing conidia (e.g., some Fusarium spp.).

Synnema (pl. Synnemae)

Bundle of conidiophores united into an erect column bearing conidia at apex or sides.

Acervulus

Saucer-shaped asexual fruiting body that erupts through host epidermis, bearing conidiophores.

Pycnidium

Flask-shaped asexual fruiting body lined with conidiophores; spores exit via an ostiole.

Spermatium

Non-germinating, minute conidium functioning as a male gamete.

Oidium (pl. Oidia)

Thin-walled hyphal cell acting as an asexual spore; sometimes functions as spermatium.

Conidiogenous cell

Specialized cell from which a conidium is produced.

Sporangiolum

Small sporangium containing few spores; cylindrical form called merosporangium.

Unitunicate ascus

Ascus with a single functional wall layer; inner and outer layers tightly fused.

Bitunicate ascus

Ascus with separable outer and inner walls; inner wall extends during spore discharge.

Prototunicate ascus

Thin-walled ascus that ruptures to release spores; typical of many yeasts.

Ascospore

Sexual spore formed inside an ascus of Ascomycota.

Basidiospore

Sexual spore produced externally on a basidium of Basidiomycota.

Zygospore

Thick-walled sexual resting spore formed by fusion of compatible gametangia in Zygomycota.

Oospore

Thick-walled sexual spore produced by fusion of oogonium and antheridium in Oomycota.

Plasmogamy

Fusion of cytoplasm from two compatible fungal cells.

Karyogamy

Fusion of nuclei resulting in diploid zygote.

Meiosis

Reductional division restoring haploid condition and generating genetic variation.

Saprophyte (saprobe)

Organism that obtains nutrients from dead organic matter.

Parasite

Organism that obtains nutrients from living host, often causing disease.

Obligate parasite (biotroph)

Parasite that can grow only on living host tissue.

Facultative saprophyte

Pathogen that can live as parasite or as saprophyte on dead material.

Facultative parasite

Normally saprophytic fungus that can become parasitic under suitable conditions.

Symbiont

Organism engaged in a mutually beneficial association with another species.

Mycorrhiza

Symbiotic association between fungal hyphae and plant roots.

Ectomycorrhiza

Mycorrhiza with external fungal sheath and Hartig net between root cortical cells.

Endomycorrhiza (VAM)

Mycorrhiza where fungal hyphae penetrate root cortical cells (e.g., arbuscular mycorrhiza).

Ectoendomycorrhiza

Mycorrhiza exhibiting features of both ecto- and endomycorrhiza.

Predacious fungus

Fungus that traps and consumes small organisms such as nematodes.

Woronin body

Dense, spherical organelle in Ascomycota that plugs septal pores after hyphal injury.

Deuteromycetes (Fungi Imperfecti)

Group of fungi known only by asexual (conidial) states; sexual stage unknown.

Coelomycetidae

Subclass of Deuteromycetes producing conidia within pycnidia or acervuli.

Hyphomycetidae

Subclass of Deuteromycetes producing free conidia on hyphae or synnemata.

Taxon

Named group of organisms at any rank in classification.

Binomial nomenclature

Two-word Latin name of a species: genus name + specific epithet.

Formae speciales (f. sp.)

Physiological forms within a fungal species distinguished by host range.

Physiologic race

Strain of a pathogen differing in virulence on host cultivars but morphologically identical.

Phylum Chytridiomycota

Primitive true fungi producing uniflagellate zoospores; mainly aquatic.

Phylum Zygomycota

Terrestrial fungi with coenocytic hyphae and zygospores; includes Mucorales.

Phylum Ascomycota

Sac fungi producing ascospores in asci; hyphae usually septate with Woronin bodies.

Phylum Basidiomycota

Fungi producing basidiospores on basidia; includes mushrooms, rusts, smuts.

Phylum Glomeromycota

Obligate endomycorrhizal fungi forming arbuscules in plant roots.

Phylum Oomycota

Water moulds with diploid coenocytic hyphae, cellulose-rich walls, and biflagellate zoospores.

Phylum Plasmodiophoromycota

Endoparasitic slime mould-like organisms causing diseases such as club root of cabbage.

Kingdom Stramenopila

Group characterized by heterokont flagella; includes Oomycota and diatoms.

Kingdom Protista (slime moulds)

Eukaryotic kingdom containing plasmodial and cellular slime moulds lacking true mycelium.

Order Mucorales

Zygomycete order with fast-growing, coenocytic saprobes or pathogens; produces sporangia.

Order Peronosporales

Oomycete order containing important plant pathogens like Phytophthora and downy mildews.

White rust

Plant disease caused by Albugo species characterized by white pustules.

Downy mildew

Foliar disease caused by obligate oomycete parasites producing downy sporulation.