Ascospores

Characteristics

Distribution
Ubiquitous.
More than 3,000 genera.

Where Found
Saprophytes and plant pathogens. Found everywhere in nature.

Mode of Dissemination
Spores are predominantly forcibly discharged during periods of high humidity or rain.

Growth Indoors
The cellulolytic ascomycetes Chaetomium and Ascotricha are frequently found growing indoors on damp substrates.

Industrial Uses
Dependent on genus and species.

Other Comments
Some of the common asexual fungi such as Penicillium and Aspergillus produce sexual forms under certain conditions; these are classified in the ascomycete group and given distinct names. For example, the most common sexual forms of Penicillium are Talaromyces and Eupenicillium; the most common sexual forms of Aspergillus are Eurotium and Emericella.

Potential Health Effects

Allergens
Highly variable, dependent on genus and species. Poorly studied.

Potential Opportunist or Pathogen
Dependent on genus and species, but the vast majority do not cause disease.

Potential Toxin Production
Very many, dependent on genus and species.

Laboratory Notes

Growth/Culture Characterisics
While some ascomycetes sporulate in culture (Chaetomium, Pleospora), many are parasitic plant pathogens, and sporulate (grow) only on living host plants.

Spore Trap Recognition
Many ascospores are distinctive. Many others will be classified as "other colorless." In general, ascospores are recognizable by the fact that they have no attachment points, and are sometimes enclosed in gelatinous sheaths or within a sac.

Tape Lift Recognition
Many ascomycetes are distinctive, and readily identified on tape samples, especially if fruiting bodies are present.