Abstract— A new species of Thismiaceae, Thismia betung-kerihunensis Tsukaya et H. Okada, found during a botanical survey of Betung-Kerihun National Park, West Kalimantan, Borneo, Indonesia, is described and illustrated. This species closely resembles Thismia
clavigera (Becc.) F. Muell, which is distributed in Borneo, Sumatra, Langkawi, and Thailand; however, it differs in flower shape, size, and color, having conspicuous hood-like appendages at the tip of the brilliant blue-green colored mitre formed by the three inner tepals. Moreover, it
differs in the shape of the anther connectives that lack acutely elongated apices and has rectangular glands. The smaller stature of the species also distinguishes it from T. clavigera.