page_title: Oomycete
section_title: Classification
hierarchical_section_title: Oomycete / Classification
caption_attribution_description: Biologische Schemata, gezeichnet und freigegeben von M. Piepenbring
context_page_description: Oomycota or oomycetes form a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms. They are filamentous, heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the result of contact between hyphae of a male antheridia and female oogonia; this spore can overwinter and is known as a resting spore. Asexual reproduction involves the formation of chlamydospores and sporangia, producing motile zoospores. Oomycetes occupy both saprophytic and pathogenic lifestyles, and include some of the most notorious pathogens of plants, causing devastating diseases such as late blight of potato and sudden oak death. One oomycete, the mycoparasite Pythium oligandrum, is used for biocontrol, attacking plant pathogenic fungi. The oomycetes are also often referred to as water molds, although the water-preferring nature which led to that name is not true of most species, which are terrestrial pathogens.
  Oomycetes were originally grouped with fungi due to similarities in morphology and lifestyle.
context_section_description: Previously the group was arranged into six orders.
  The Saprolegniales are the most widespread. Many break down decaying matter; others are parasites.
  The Leptomitales have wall thickenings that give their continuous cell body the appearance of septation. They bear chitin and often reproduce asexually.
  The Rhipidiales use rhizoids to attach their thallus to the bed of stagnant or polluted water bodies.
  The Albuginales are considered by some authors to be a family (Albuginaceae) within the Peronosporales, although it has been shown that they are phylogenetically distinct from this order.
  The Peronosporales too are mainly saprophytic or parasitic on plants, and have an aseptate, branching form. Many of the most damaging agricultural parasites belong to this order.
  The Lagenidiales are the most primitive; some are filamentous, others unicellular; they are generally parasitic.
  However more recently this has been expanded considerably.
  Anisolpidiales Dick 2001
  Anisolpidiaceae Karling 1943
  Lagenismatales Dick 2001
  Lagenismataceae Dick 1995
  Salilagenidiales Dick 2001
  Salilagenidiaceae Dick 1995
  Rozellopsidales Dick 2001
  Rozellopsidaceae Dick 1995
  Pseudosphaeritaceae Dick 1995
  Ectrogellales
  Ectrogellaceae
  Haptoglossales
  Haptoglossaceae
  Eurychasmales
  Eurychasmataceae Petersen 1905
  Haliphthorales
  Haliphthoraceae Vishniac 1958
  Olpidiopsidales
  Sirolpidiaceae Cejp 1959
  Pontismataceae Petersen 1909
  Olpidiopsidaceae Cejp 1959
  Atkinsiellales
  Atkinisellaceae
  Crypticolaceae Dick 1995
  Saprolegniales
  Achlyaceae
  Verrucalvaceae Dick 1984
  Saprolegniaceae Warm. 1884 [Leptolegniaceae]
  Leptomitales
  Leptomitaceae Kuetz. 1843 [Apodachlyellaceae Dick 1986]
  Leptolegniellaceae Dick 1971 [Ducellieriaceae Dick 1995]
  Rhipidiales
  Rhipidiaceae Cejp 1959
  Albuginales
  Albuginaceae Schroet. 1893
  Peronosporales [Pythiales; Sclerosporales; Lagenidiales]
  Salisapiliaceae
  Pythiaceae Schroet. 1893 [Pythiogetonaceae; Lagenaceae Dick 1994; Lagenidiaceae; Peronophythoraceae; Myzocytiopsidaceae Dick 1995]
  Peronosporaceae Warm. 1884 [Sclerosporaceae Dick 1984]
caption: Simplified phylogeny.
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