Indo-Malaysia/Northern Australia, Equatorial Africa, Tropical South and Central America, North America, Extratropical South America, Eastern Asia, Southern Australia and New Zealand, South Africa, Temperate Eurasia and,
Wnally, the circumpolar and high mountain regions. The number of species supposed to be endemic to any of those regions roughly speaking decreases from over a hundred to less than 10 and presumably goes hand in hand with the total desmid species diversity to be encountered.