1. Fungi - Plant-like organisms with no chlorophyll, with a definite nuclei and usually rigid cell walls. |
2. Hyphae - Long chains of cells that are aggregated into mats termed "mycelium." |
3. Fungi reproduce by spores, which may be sexually (nuclear fusion, meiosis) formed or asexually (mitotically) formed. |
4. Fungal classes according to their method of sexual reproduction. |
a. 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. |
b. Zygomycetes produce a single, large thick-walled sexual spore with each nuclear fusion. Zygomycetes also produce asexual spores in sporangia sacs (eg, Rhizopus, Mucor). |
c. Ascomycetes produce eight sexual spores in a sac called an ascus and asexual spores called conidia (eg, Leptosphaeria, Chaetomium, Venturia). |
d. Basidomycetes form sexual spores externally on pegs produced on structures called basidia. |
i. Heterobasidiomycetes produce separate septate basidia (eg, rusts and smuts). |
ii. Holobasidiomycetes produce single-celled, club-shaped basidia (eg, mushrooms and puffballs). |
e. Deuteromycetes are fungi for which a sexual stage has not been identified (Aspergillus, Stemphylium, Alternaria, Cladosporium). |
f. 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. |
g. Actinomycetes are filamentous bacteria that produce dry airborne spores. |