Subtribe Tropidiinae Pfitz. Entw. Nat Anord. Orch.: 99.1887.
Velamen of the Calanthe type. Stem reed-like, woody, sometimes branched. Leaves spirally arranged, convolute, plicate. Inflorescence terminal or lateral. Flowers resupinate or not, tubular or saccate at the base. Lip fixed, more or less constricted near the apex. Seeds of Goodyera type.
Column foot short, rudimentary or none. Gynostemium erect, elongate and slender to short and massive. Staminodes wing-like, formed of inflated cells, fused with the filament and the style below the stigma, or rudimentary, or completely reduced. Stigma transversally elliptic, sometimes horizontal or Lilium-like.
Rostellum elongate, beak-like, erect, massive, acute. Viscidium single, oblong, multi-layered, its inner surface covered by sclerenchymatous cells. Hamulus thick and fleshy, formed of two layers of cells; the lower one sclerenchymatous, and the upper of a large-celled, often papillate, epidermis. Rostellum remnant bidentate. Filament reduced, completely incorporated into the column part. Anther narrowly cordate to oblong, 2-chambered, movable. Connective fleshy, forming a thick pad above the chambers. Endothecial thickenings of type I. Anther base situated below stigma base.
Pollinia attenuate towards the apex, rounded at the base, sectile.