Microsorum aurantiacum, a new species of microsoroid ferns

The genus Microsorum, of which a revision will be published in the near future, consists of 50 species, including the here described M. aurantiacum. In Microsorum several groups may be distinguished, all linked by one to several intermediate species. Microsorum aurantiacum finds its nearest allies in the group of species that formerly were distinguished as the genus Phymatosorus. Although the type, which is also the only collection as yet, was collected already in 1909, reportedly with many duplicates, it remained unnamed, sitting in the herbarium of Berlin. It is easily distinguished from its allies in the nearly circular leaves with very narrow lobes.