Abstract: The genus Macromitrium is one of the most taxonomically difficult genera in bryophytes. Until now 946 specific names have been reported in Macromitrium, of which 351 have been accepted. The species of Macromitrium in many countries and areas have been taxonomically reviewed, which included the Central America, Asia, Australia, New Zealand and the Southern Africa, whereas those in the South America, Central Africa and Madagascarare still poorly understood and are in urgent need of taxonomic revision. Although there are many views and controversies on the classification of Macromitrium, there is not yet a preliminary and widely recognized classification system of the genus Macromitrium. Macromitrium is rich in species and has a worldwide distribution, so we need an international cooperation to conduct a comprehensive taxonomic revision and systematics study on the genus Macromitrium in the world.

Key words: Macromitrium, taxonomic revision, systematics, problems