the Myxogastriae are morphologically very plastic, which is to say susceptible to environmental influences; only a few characteristics are diagnostic for a small number of species. In the past authors have unsuccessfully tried to describe a new taxon based on a small number of examples, but this leads to numerous duplications, sometimes even at genus level. For example, Squamuloderma nullifila is actually a species from the genus Didymium. Classification and phylogeny The following classification is based on Adl et al. (2005) while the classes and further divisions on Dykstra & Keller (2000) who included the Myxogastria in Mycetozoa. The sister taxon is the subclass Dictyostelia. Together with the Protostelia they formed the taxon Eumycetozoa. Other subclasses differ from the other species mainly in the development of fruit bodies; while Protostelia create a separate fruit body from each single mononuclear cell, Dictyostelia develop cell complexes – the so-called pseudo-plasmodia – from separate cells, which then become fruit bodies. Clade Myxogastria (or myxomycetes) Class Ceratiomyxomycetes Hawksworth, Sutton & Ainsworth 1983 Order Ceratiomyxida Martin 1949 ex Farr & Alexopoulos 1977 Order Protosporangiida Shadwick & Spiegel 2012 Class Myxomycetes Link 1833 em. Haeckel 1866 Subclass Lucisporomycetidae Leontyev et al. 2019 (Clear‑spored acellular slime moulds) Superorder Cribrarianae Leontyev 2015 Order Cribrariales Macbride 1922 Family Cribrariaceae Rostafinski 1873 Superorder Trichianae Leontyev 2015 Order Reticulariales Leontyev 2015 Family Reticulariaceae Rostafinski 1873 Order Liceales Jahn 1928 Family Liceaceae Rostafinski 1873 Order Trichiales Macbride 1922 Family Dianemidae Macbride 1899 Family Trichiidae Rostafinski 1826 Subclass Collumellidia Leontyev et al. 2019 (Dark‑spored acellular slime moulds) Order Echinosteliopsidales Shchepin et al. Family Echinosteliopsidaceae Olive 1970 Superorder Echinostelianae Leontyev 2015 Order Echinosteliales Martin 1961 Family Echinosteliaceae Rostafinski ex Cooke 1877 Superorder Stemonitanae Leontyev 2015 Order Clastodermatales Leontyev et al. 2019 Family Clastodermataceae Alexopoulos & Brooks 1971 Order Meridermatales Leontyev 2015 Family Meridermataceae Leontyev 2015 Order Stemonitales Macbride 1922 Family Comatrichaceae Leontyev 2015 Family Stemonitidaceae Fries 1829 Order Physarales Macbride 1922 Family Didymiaceae Rostafinski ex Cooke 1877 Family Lamprodermataceae Leontyev 2015 Family Physaraceae Chevallier 1826 Some classifications place part of the orders above in the subclass Myxogastromycetidae. Characteristics and life cycle Monocellular, mononuclear phase Spores The spores of Myxogastria are haploid, mainly round and measure between 5 μm and 20 μm, rarely up to 24 μm in diameter. Their surface is generally reticular, sharp, warty or spiky and very rarely smooth. The typical colour of the spore mass becomes visible through the structure, since