Abstract
Bulbophyllum romklaoense (B. sect. Lemniscata) from northern Thailand is described and illustrated as a species new to science. It is most similar to B. muscarirubrum and B. triste, but differs by having inflorescences with only 4–6 reddish-brown flowers, falcate-subovate lateral sepals that are connate only in the upper half along the interior margins, petals with erose to fimbriate margins and a lip with long cilia in the distal half on the lower surface. A comparison with other similar species in the section, as well as notes on ecology, phenology, conservation assessment and a key to B. sect. Lemniscata in Thailand are also provided.