The Pleosporales is the largest order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 in the fungal class Dothideomycetes

Dothideomycetes

Dothideomycetes is the largest and most diverse class of ascomycete fungi. It comprises 11 orders 90 families, 1300 genera and over 19,000 known species. Traditionally, most of its members were included in the loculoascomycetes, which is not part of the currently accepted classification...

. By some estimates it contains 23 families

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

, 332 genera

Genera

Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...

 and more than 4700 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

. The majority of species are saprobes on decaying plant material in fresh water, marine, or terrestrial environments, but several species are also associated with living plants as parasites

Parasitism

Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...

, epiphyte

Epiphyte

An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...

s or endophyte

Endophyte

An endophyte is an endosymbiont, often a bacterium or fungus, that lives within a plant for at least part of its life without causing apparent disease. Endophytes are ubiquitous and have been found in all the species of plants studied to date; however, most of these endophyte/plant relationships...

s. The best studied species cause plant diseases on important agricultural crops e.g. Cochliobolus heterostrophus

Cochliobolus heterostrophus

Cochliobolus heterostrophus is a fungal plant pathogen. It can cause Southern Corn Leaf Blight in Maize.Cochliobolus heterstrophus is found in many tropical regions and in the southern part of the US. Cochliobolus, although not currently the most economically serious disease, can be a very...

, causing southern corn leaf blight on maize

Maize

Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...

, Phaeosphaeria nodorum

Phaeosphaeria nodorum

Phaeosphaeria nodorum is a major fungal pathogen of wheat and a member of the Dothideomycetes, a large fungal taxon that includes many important plant pathogens affecting all major crop plant families....

(Stagonospora nodorum) causing glume blotch on wheat

Wheat

Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...

 and Leptosphaeria maculans

Leptosphaeria maculans

Leptosphaeria maculans is a fungal pathogen that is the causal agent of blackleg disease on Brassica crops. The major yield loss is due to stem canker....

causing a stem canker (called blackleg) on cabbage crops (Brassica

Brassica

Brassica is a genus of plants in the mustard family . The members of the genus may be collectively known either as cabbages, or as mustards...

). Some species of Pleosporales occur on animal dung and a small number occur as lichen

Lichen

Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...

s and rock-inhabiting fungi. The oldest member of Pleosporales is the extinct genus Margaretbarromyces

Margaretbarromyces

Margaretbarromyces is an extinct monotypic genus of pleosporale fungus of uncertain family placement. At present it contains the single species Margaretbarromyces dictyosporus....

which was described from Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 age strata on Vancouver Island

Vancouver Island

Vancouver Island is a large island in British Columbia, Canada. It is one of several North American locations named after George Vancouver, the British Royal Navy officer who explored the Pacific Northwest coast of North America between 1791 and 1794...

, British Columbia.