The image here represents the Aleuria aurantia, a member of the Ascomycota family (See links page). Basidiomycota and Ascomycota are the most closely related fungi, and are sometimes known as 'Higher' fungi. They share a number of traits, including a dikaryotic stage in the life cycle, complex dispersal patterns, a compartmentalised mycelium and plectenchymatous structures related to spore production. There is plenty of evidence, both morphological and molecular, that the two diverged from a common ancestor. Molecular sequence data indicates the two diverged from one another in the Paleozoic period, about 500 million years ago. 

In general, Ascomycota are typically mycelial with cross-walls, or sometimes yeast. Sexual reproduction is by fusion of modified hyphae or yeasts. It sometimes occurs by fusion of a 'male' spore (spermatium) with a 'female' receptive hypha (trichogyne) leading to the production of an ascus containing ascospores. Asexual reproduction may be carried out by fission, fragmentation or formation of conidia, according to species and environmental conditions. Fungi that cannot reproduce sexually are often classed into an artificial grouping known as Deuteromycota. It accommodates a large number of fungi, mainly constituting Ascomycota. A number of important Ascomycota belong in this group, including Penicillium, Aspergillus, Trichoderma and Fusarium.

The Ascomycota is an extremely large and important group, divided into three subgroups. An early radiation in the timeline established the Archiascomycetes, a diverse group of fungi with and without hyphal fruiting bodies. The group includes the fission yeasts, Schizoaccharomyces spp. and the animal pathogen Pneumocystis carinii. Another primary group is the Hemiascomycetes, sometimes known as the Saccharomycetales. This group includes the budding yeast Saccharomyces cerevisiae and Pichia spp. which are common on fruit surfaces. The final group is known as the Euascomycetes, or the filamentous ascomycetes. Though the divergence lineage is unclear for the Euascomycetes, all groups share similar features such as long, slender asci arranged in a single layer in a fruiting body. There are four major groups of filamentous ascomycetes. The Plectomycetes (Eurotiales, Onygenales) and Loculoascomycetes (Chaetothyriales) are one group. The Pyrenomycetes (Hypocreales, Microascales, Diaporthales, Sordariales) and Loculoascomycetes (Pleosporales) constitutes another. The operculate discomycetes (Pezizales) a third and the inoperculate discomycetes (Geoglossaceae) the final.