Gastrorchis Thouars, Nouv. Bull. Sci. Soc. Philom. Paris 10: 317 (1809).
Gastrorkis Schltr., Repert. Spec. Nov. Regni Veg. Beih. 33: 166 (1924), orth. var.
Plants with the appearance of Calanthe or Phaius, but much larger, with very large leaves and very brilliantly colored flowers of various tints; flowers cup-shaped, sub-spherical, with 3 more or less projecting angles. Sepals oval, all free. Labellum free, flat and widely auriculate; labellum provided with a large V shaped callus or crest, keels and often a large number of hairs behind; spur nearly absent. Column 15 mm long. Anther glabrous or hearing several hairs, provided apically with a truncate appendage: staminodes only slightly present as enlarged areas of the clinandrium margins; pollina 8 in 2 groups of 4 (2 longer and 2 shorter in each set), each group joined by a single cauda, which are separated, long (I .5 mm) and thick. Rostellum entire, in the form of a flap. truncate apically.

Gastrorchis francoisii Schltr. Madagascar.
Gastrorchis humblotii (Rchb.f.) Schltr. Madagascar.
Gastrorchis humblotii var. humblotii. Madagascar.
Gastrorchis humblotii var. rubra (Bosser) Bosser & P.J.Cribb   C. Madagascar.
Gastrorchis humblotii var. schlechteri (H.Perrier) Senghas ex Bosser & P.J.Cribb N. Madagascar.
Gastrorchis lutea (Ursch & Toill.-Gen. ex Bosser) Senghas   NE. Madagascar.
Gastrorchis lutea var. geffrayi (Bosser) J.V.Stone & P.J.Cribb N. Madagascar
Gastrorchis lutea var. lutea N. & ENE. Madagascar
Gastrorchis peyrotii (Bosser) Senghas  NE. Madagascar.
Gastrorchis pulchra Humbert & H.Perrier  Madagascar.
Gastrorchis simulans (Rolfe) Schltr. NE. Madagascar.
Gastrorchis steinhardtiana Senghas  N. & ENE. Madagascar
Gastrorchis tuberculosa (Thouars) Schltr. NE. Madagascar.
Gastrorchis villosa (Thouars) J.V.Stone & P.J.Cribb   S. & SE. Mauritius, SSE. Réunion

World Checklist of Monocotyledons. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; accessed 26/06/2020
Bibliography and References:
Masuda Y, Faliniaina L, Kondo K. 2006 Phylogenetic analysis of Malagasy Gastrorchis and Phaius (Orchidaceae) based on internal transcribed spacer (ITS) sequence. J. Phytogeogr. Taxon. 54. (1): 15-20.
Senghas K. 1997 Die Gattung Gastrorchis, mit einer neuen Art, Gastrorchis steinhardtiana. J. Orchideenfreund 4. (3): 130-134 (1997)