Microglossum capitatum: taxonomy and conservation.

Microglossum capitatum was originally described based on specimens collected from tropical China. The name was previously considered a synonym for M. longisporum due to similar ascospore characteristics. A recently described species, M. macrosporum, from northern Thailand is very similar to M. capitatum in morphology. Using four recently collected samples from the type locality of M. capitatum, the systematic relationship and taxonomic position of this species were reanalyzed based on morphological and three-locus evidences. Our data suggested that M. longisporum is clearly different from M. capitatum by its cinnamon-brown clavate apothecia and subtropical to temperate ecological habitats. Further studies indicated that M. capitatum and M. macrosporum belong to the same species, and, thus, the latter should be treated as a synonym of the former. Our field observations suggested that M. capitatum has been facing severe threats of habitat loss and degradation, and it is urgent to protect this species.