Thismia sumatrana from West Sumatra, Indonesia (from the holotype). A Flower B Dome-shaped mitre bearing the eaves-like to hood-like accessory lobes. The accessory lobes are indicated using the arrows C Upper part of perianth tube. Outer perianth lobes are indicated by arrows D Inner view of two pendulous stamens. Thecae and glands are indicated by upper and lower arrows, respectively E Outer view of a pendulous stamen. Thecae and glands are indicated by upper and lower arrows, respectively. One grid is equal to 1 mm2.