THE ASCOMYCOTA
Click to see photos of fungi belonging to the following Orders:
BOLINALES, GEOGLOSSALES, HYPOCREALES, NEOLECTA, ORBELIALES, PEZIZALES, PLEOSPORALES, XYLARIALES
The function of fungal fruiting bodies is to produce and disperse sexual spores. The macrofungi on these pages are divided into two major categories or phyla; the Ascomycota and the Basidiomycota, in accordance with the manner in which there spores are formed. Sexual spores produced by macro fungi combine genetic material from two compatible parents.
With roughly 65,000 species, the largest numbers of fungi are in the Ascomycota phyla. They include single-celled yeasts, lichens, and macro fungi such as morels and truffles. Their spores are produced in sac-like cells called asci. Each ascus contains eight spores. (Note: There are exceptions to this general statement).
Three subphyla constitute the Ascomycota: the Pezizamycotina, the Saccharomycotina and the Taphrinomycotina. The largest division is the Pezizomycotina, which includes all ascos that produce ascocarps, (with the exception of Neolecta, Taphrina, Archaeorhizomyces. It is in the Taphrinomycotina.). The “true’ single-celled yeasts, which reproduce asexually by budding, comprise the Saccharomycotina. The Taphrinomycota include hyphal fungi like fission yeasts Schizosaccharomyces and the lung fungus, Pneumocytis.
Phylogenetic analyses suggest a monophyletic Ascomycota. It is believed the three divisions evolved from a single species formed at least 400 million years ago in the early Devonian. Other estimates suggest the animal and the fungal kingdom first made their respective appearances a billion years ago after diverging from ancestral parents – flagellated protists – during the transition from aquatic to terrestrial habitats.
There are several general shapes and textures common to ascomycetous fungi. The shallow cup-shaped fungi have been called discomycetes. The asci and spores of such fungi are arranged vertically within the interior of the cup, and are also called the apothecium.
Club-shaped fungi like the Geoglossum andTrichoglossum sport the apothecium with its acsi and spores on the external surface of the ‘cap’.
Morels have an even more complicated apothecium consisting of many depressions and ridges on the outer surface bearing the asci and spores.
Flask fungi come in a variety of shapes and textures from rubbery to hard. They usually produce spores in spherical chambers called perithecia.
Like the Basidiomycota, the Ascomycota are heterotophic. They secrete enzymes, which enable them to decompose organic matter like cellulose and lignin and absorb the nutrients released. If parasites or mutualistic symbionts, they colonize plants, animals or other fungi and get their energy needs met from their hosts.
The following photos depict some of the more obvious ascomycetous fungi found in northeastern North America. They are organized aphabetically by order, family and then by genus beginning with the BOLINIALES.
BOLINALES GEOGLOSSALES HYPOCREALES NEOLECTA ORBELIACEAE PEZIZALES PLEOSPORALES XYLARIALES