One genera
    ~15-20 species

"The single genus of the family, Orchidantha, with 15-20 species, is found in Southeast Asia and some Pacific Islands. Orchidantha has always been considered an unusual member of the Zingiberales and is among the most poorly known taxa in the order in terms of botany and horticulture. The specialized leaf blade with several pairs of longitudinal veins parallel to the distinct midrib, the often subterranean inflorescence, and the elaboration of one petal into a large labellum are among the more distinctive features of the family. Several species, for example O. maxillarioides and O. fimbriata, are cultivated in some botanic gardens. The name Orchidantha signifies the orchid-like shape of the flowers."  - description via Smithsonian NMNH

For more information:

Lyon PDFs

Orchidantha sp.

Orchidantha sp.