Thismia daemona (Thismiaceae), a new species from Thailand supported by morphological and molecular evidence.

A new species of Thismia from Thailand, T. daemona is described based on morphological characters and molecular phylogenetic analyses. Morphological characters were examined from fresh and spirit materials using a stereo microscope. Phylogenetic analyses were conducted based on three nuclear (SSU, ITS, LSU) and two mitochondrial (atpA, matR) markers. The new species is characterized by coralliform roots, blackish flowers, reddish orange and fleshy outer tepals, inner tepals forming a mitre with three slender claviform appendages, inner surface of floral tube possessing irregular transverse bars in lower half and finely reticulations in upper half, epidermis of transverse bars and reticulations covered with white translucent trichomes, and translucent blue stamens with recurved apex. Phylogenetic analyses support its placement within Thismia sect. Geomitra, with a sister relationship to T. betung-kerihunensis. In addition, the new species is assessed as Critically Endangered according to the IUCN Red List categories and criteria.