Abstract
Thismia selangorensis, a distinct mitriform species of the mycoheterotrophic genus Thismia, is described herein. It was first discovered in a tree hole on a riverbank in Taman Eko Rimba Sungai Chongkak, Selangor, Malaysia. This new species is superficially similar to members of Thismia section Geomitra in that it has coralliform roots, inner tepals forming a mitre with three appendages on top, and stamens with a prominent dorsal rib. However, T. selangorensis differs from known species of T. sect. Geomitra in several morphological features, including the colour of the flowers, the shape of the mitre, the shape of the inner tepal lobes forming the mitre, and the presence of translucent reticulation on the inner surface of the floral tube. Thismia selangorensis is provisionally classified as Critically Endangered according to the IUCN Red List categories and criteria.