A new section in Asian Thismia (Thismiaceae), T. sect. Mirabiles, and its checklist

The paper continues a series of contributions aimed to develop a phylogenetically sound sectional subdivision of the mycoheterotrophic genus Thismia. Here, a formal taxonomic status is provided for a remarkable monophyletic Asian group of species that is also well-defined morphologically within the genus. It is demonstrated that no supraspecific taxon name of any rank is available for this group. Hence, a new section, Thismia sect. Mirabiles, is established. Inconsistencies are highlighted in the earlier treatments where the species placed here in Thismia sect. Mirabiles were assigned to Thismia sect. Sarcosiphon. Indeed, in all such treatments, either the taxon monophyly or the nomenclatural applicability of the latter sectional name is violated. A checklist of the newly described section is provided along with an identification key to its species. The section is currently known to comprise eight species mainly distributed in mainland Southeast Asia and including a species endemic to the Andaman and Nicobar Islands.