Term
Definition
Ascus
Saclike cell where meiosis (and often post-meiotic mitosis) occurs, typically producing 8 ascospores; the meiosporangium of ascomycetes. Example: Peziza, Neurospora.
Ascus Types
Three wall types: Prototunicate (thin wall, dissolves), Unitunicate (single wall, opens via lid), Bitunicate (‘jack-in-the-box’ double wall mechanism).
Crozier
Hook-like structure at the tip of ascogenous hyphae that maintains the dikaryotic state during nuclear division; analogous to clamp connections in basidiomycetes.
Dikarya
Fungal subkingdom including Ascomycota and Basidiomycota; members possess dikaryotic (n+n) cells during part of their life cycle.
Ascocarp
Multicellular fruiting body of ascomycetes containing asci and ascospores; includes apothecia, perithecia, cleistothecia, pseudothecia, and gymnothecia.
Apothecium
Cup-shaped open ascocarp with exposed hymenium for spore discharge. Example: Peziza, Morchella (morels).
Perithecium
Flask-shaped ascocarp with a pore (ostiole) for spore release. Example: Nectria, Cordyceps.
Cleistothecium
Closed, spherical ascocarp without an opening; asci released after wall breaks down. Example: Aspergillus, Penicillium.
Conidia
Asexual, non-motile spores produced by mitosis, not inside a sporangium; used for rapid propagation. Example: Penicillium, Aspergillus.
Conidiophore
Specialized hyphal stalk bearing conidia. Example: Brush-like in Penicillium, columnar in Aspergillus.
Conidiomata
Structure enclosing or supporting conidiophores; includes Pycnidia (enclosed), Sporodochia (cushion-like), and Synnemata (columnar clusters).
Anamorph
Asexual (mitotic) life stage of a fungus, producing conidia. Example: Fusarium (anamorph of Nectria); also called fungi imperfecti.
Teleomorph
Sexual (meiotic) life stage of a fungus forming asci or basidia. Example: Nectria (teleomorph of Fusarium).
Dual Nomenclature
Old system giving fungi with sexual and asexual stages two names (e.g., Fusarium/Nectria). Now replaced by ‘one fungus, one name’ rule.
Photobiont
Photosynthetic partner (green alga or cyanobacterium) in a lichen, providing carbohydrates to the fungal mycobiont. Example: Trebouxia (green alga).
Lichen Thallus Layers
Typical layers: Upper cortex → Photobiont layer → Medulla → Lower cortex (may have rhizines).
Crustose Lichens
Crust-like and tightly attached to substrate; cannot be removed without damage. Example: Graphis species.
Foliose Lichens
Leaf-like, flat with distinct upper/lower surfaces, often attached by rhizines. Example: Parmelia species.
Fruticose Lichens
Shrub-like or hair-like lichens that may be upright or hanging. Example: Cladonia rangiferina (reindeer lichen).
Isidia
Small wart- or finger-like surface outgrowths containing both fungal and algal cells; break off for asexual reproduction.
Soredia
Powdery clusters of fungal hyphae and algal cells dispersed for vegetative propagation.
Lichen Symbiosis
Lichens are symbioses between a fungal mycobiont and one or more photobionts; can be mutualistic or parasitic depending on conditions.
