- Fungi - Plant-like organisms with no chlorophyll, with a definite nuclei and usually rigid cell walls.
|
- Hyphae - Long chains of cells that are aggregated into mats termed "mycelium."
|
- Fungi reproduce by spores, which may be sexually (nuclear fusion, meiosis) formed or asexually (mitotically) formed.
|
- Fungal classes according to their method of sexual reproduction:
|
- Oomycetes produce motile, thick-walled sexual spores, one for each nuclear fusion (eg, the downy mildews). Some oomycetes produce unispore sacs called "sporangia" that become airborne.
|
- Zygomycetes produce a single, large thick-walled sexual spore with each nuclear fusion. Zygomycetes also produce asexual spores in sporangia sacs (eg, Rhizopus, Mucor).
|
- Ascomycetes produce eight sexual spores in a sac called an ascus and asexual spores called conidia (eg, Leptosphaeria, Chaetomium, Venturia).
|
- Basidomycetes form sexual spores externally on pegs produced on structures called basidia.
|
- Heterobasidiomycetes produce separate septate basidia (eg, rusts and smuts).
|
- Holobasidiomycetes produce single-celled, club-shaped basidia (eg, mushrooms and puffballs).
|
- Deuteromycetes are fungi for which a sexual stage has not been identified (Aspergillus, Stemphylium, Alternaria, Cladosporium).
|
- Myxomycetes are organisms with both plant and animal characteristics (eg, slime molds). The vegetative stage is an amoeba or multinucleate plasmodium that moves and ingests foods.
|
- Actinomycetes are filamentous bacteria that produce dry airborne spores.
|
