Myanmar is situated in Southeast Asia, where species richness and diversity are very high. Myanmar orchid flora is very rich, but still poorly known because botanical explorations have sharply decreased in Myanmar since 1950. The present study provides a checklist of Myanmar orchid flora which includes 1040 species and 151 genera currently known from Myanmar, based on the herbarium specimens, literature and online databases. The number of species is increased by approximately 200 species more than that given in the checklist of Kress et al. (2003), mainly due to recent discoveries of new species to science and new records for Myanmar. There are 76 endemic species of Orchidaceae in Myanmar. It is estimated that ca. 150–300 species still remain as unidentified and are expected to be discovered in further studies on Myanmar orchid flora.

Odontochilus putaoensis, a new species of Orchidaceae, is described and illustrated from Putao Township, Kachin State, Myanmar. Odontochilus putaoensis is close to O. duplex, but can be easily distinguished from the latter by having a light yellow lip, a bisaccate hypochile with a small, erect, blade-like and emarginate callus within each sac, a mesochile with a pair of dentate-pectinate flanges and a bilobed epichile with a pair of widely diverging lobes that are erect and concave. An identification key to the Southeast Asian species of Odontochilus and colour photographs of O. putaoensis are provided. A preliminary conservation assessment according to the IUCN Red List Categories and Criteria is given for the new species.

Liparis popaensis, a new species of Orchidaceae, is described from Popa Mountain National Park, central Myanmar. Liparis popaensis is morphologically similar to L. odorata but it differs from the latter by having oblong-lanceolate dorsal sepal, column with two triangular wings and lip with a pair of subconical and basally adjoining calli at its base. Identification key and colour photographs are provided. A preliminary conservation assessment according to the IUCN Red List Categories and Criteria is given for the new species.