Author:
Jan Scholten
Book:
Qjurious
Type:
Info
Chapter:
3-750.00.00
Ascomycota
English: Sac fungi; Ascomycetes.
Botany: 64000 species; the ascus, meaning "sac" or "wineskin", a microscopic sexual structure in which nonmotile spores, called ascospores, are formed, though some are asexual without asci.
Taxonomy
The classification of Fungi has been difficult. But 2 main groups have been recognised for a long time Ascomycota and Basidiomycota. The classification of Ascomycota has been more diffcult.
The Ascomycota can be grouped in several ways. One is in:
1. Hemiascomycetes = Saccharomycotina
They are mostly the Saccharomycetales, the first diverging lineage of Ascomycota.
2. Protomycetes = Taphrinomycotina
They are mostly the Saccharomycetales, the second diverging lineage of Ascomycota.
3. Euasocomycetes = Pezizomycotina
The majority of Ascomycota. ik can be split in 4 clades
1. Plectomycetidae, also named Eurotiomycetes
2. Pyrenomycetidae
1. Taphrinomycetidae = Protomycetes = Taphrinomycotina
2. Eurotiomycetes = Plectomycetidae = Prototunicatae = Onygenidae
3. Sordariomycetes = Pyrenomycetidae = Unitunicatae inoperculatae 1
4. Leotiomycetes = Pyrenomycetidae = Unitunicatae inoperculatae 2
5. Pezizetidae = Unitunicatae operculatae
Characteristics
1. Vegetative body is unicellular or commonly well developed, branched septate mycelium with uni- or multinucleate cells having perforated septa.
2. Mostly, the cell wall is composed of chitin and glucans, but in unicellular form, it is composed of glucans and mannans.
3. Vegetative reproduction takes place by fragmentation (in filamentous form), fission and budding (in unicellular form).
4. Asexual reproduction takes place by non-motile spores, such as conidia, oidia and chlamydospores.
5. Sexual reproduction takes place by gametangial copulation (Saccharomyces), gametangial contact (Penicillium), somatogamy (Morchella) or spermatiza- tion (Polystigma).
6. Complete absence of motile structures.
7. The product of sexual reproduction is the ascospores grown inside a small specialised sac-like structure, called ascus.
8. The fruit bodies (inside which ascus developed) are the ascocarps. The asco- carps may be cleistothecium (Penicilliumi), apothecium (Ascobolus), perithecium (Daldenia) or ascostroma (Elsinoe veneta).
Subclasses
Pezizomycotina
Arthoniomycetes
Coniocybomycetes
Dothideomycetes
Eurotiomycetes
Geoglossomycetes
Laboulbeniomycetes
Lecanoromycetes
Leotiomycetes
Lichinomycetes
Orbiliomycetes
Pezizomycetes
Sordariomycetes
Xylonomycetes
"Unplaced orders"
Lahmiales
Itchiclahmadion
Triblidiales
Saccharomycotina
Saccharomycetes
Taphrinomycotina
Archaeorhizomyces
Neolectomycetes
Pneumocystidomycetes
Schizosaccharomycetes
Taphrinomycetes