Fungal Morphology for the Clinical Laboratory


Definitions and Nomenclature:

Anamorph
Asexual or "imperfect" form of a fungus; for example, Scedosporium apiospermum is the anamorphic form of the teleomorph Pseudallescheria boydii
Annellide
A conidiogenous cell that extends and retracts as it produces conidia, often leaving a succession of scars or rings
Apophysis
A broadening near the apex of the sporangiophore, subjacent to the columella
Arthroconidia
Conidia arising from pre-existing cells in the mycelium; adjacent cells collapse to release the mature form; see, for example, Geotrichum
Ascospore
Sexual spore produced in a sac-like structure called an ascus
Biseriate
Phialide supported by metula; see, for example Aspergillus terreus. See also Uniseriate and Metula, below.
Blastoconidia
One of three types of vegetative "spore" arising directly from the vegetative mycelium; budding form, e.g. seen in yeasts
Cleistothecia
(singular cleistothecium) A large, round structure in which asci and ascospores form; see, for example, Sepedonium
Chlamydoconidia
Conidia arising from pre-existent cells in the hyphae, which thicken and enlarge; may be intercalary, sessile, or terminal
Columella
The swollen, dome-shaped tip of a sporangiophore that extends into the sporangium
Conidia
(singular conidium) Asexual "spores" of fungus
Conidiophore
Specialized hyphal element bearing conidia
Denticle
A narrow, delicate projection bearing a conidium or sporangiolum; see, for example, Cunninghamella
Holomorph
Taxonomic name including teleomorphic and anamorphic forms of a fungus; the name of the teleomorph also serves as the name of the holomorph
Hyphae
(singular hypha) The fundamental, threadlike structure of molds
Metula
(plural metulae) Structure below the phialide in some Penicillium and Aspergillus species; see for example Aspergillus terreus
Mycelium
(plural mycelia) The mass of filaments that constitutes the body of a mold; may be vegetative or aerial (reproductive)
Perithecia
Large, round to pear-shaped structure containing asci and ascospores; a small, round opening distinguishes this from Cleistothecia; see, for example, Chaetomium spp.
Phialide
A conidiogenous cell that produces conidia from within its apex, which does not increase in width or length during conidiogenesis
Rhizoid
Root-like, branched hyphae which usually extend into growth medium; found especially in Zygomycetes. See, for example, Rhizopus
Sporangia
A fruiting body which forms a closed sac; see, for example, Absidia , Rhizopus
Sporangiophore
A specialized hyphal element that bears the sporangium
Sporodochia
A clump of conidiophores; see, for example, Epicoccum
Stolon
Horizontal hyphae growing along the surface of growth medium; runner
Teleomorph
Sexual or "perfect" form of a fungus; see Anamorph and Holomorph, above
Uniseriate
Phialide forming directly on vesicle; as, for example, Aspergillus fumigatus. See also Biseriate, above.

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Copyright © 2001, William McDonald, M.D.
Revised: 21 October 2002