Benthamia madagascariensis (Rolfe) Schltr., Beih. Bot. Centralbl. 34(2): 300 (1916).
Homotypic Synonyms:
Holothrix madagascariensis Rolfe, J. Linn. Soc., Bot. 29: 55 (1891).
Habenaria madagascariensis (Rolfe) Schltr., Oesterr. Bot. Z. 49: 23 (1899).
Peristylus madagascariensis (Rolfe) Rolfe, Orchid Rev. 7: 4 (1899).
Platanthera madagascariensis (Rolfe) Kraenzl., Orchid. Gen. Sp. 1: 609 (1899).
Heterotypic Synonyms:

Peristylus macropetalus Finet, Notul. Syst. (Paris) 2: 25 (1911).
Description:

Plants terrestrial, 25-50 cm tall; leaves 3-4. linear (8-15 cm x 3-5 mm) on the lower half of the stem: with 3-4 sheaths above with a narrow limbus. Inflorescence 5-10 cm, flowers very densely arranged, unilateral, white; bracts narrow, very acute. Sepals 1 veined, all linear, 7 mm long, the laterals slightly shorter, adnate basally with the labellum and petals. Petals larger (8-9 mm) and wider, oblanceolate linear, rounded apically, 1veined. Labellum 8-9 mm long. Narrow, divided into 3 lobes in the apical quarter; lobes equal, 3 mm long; spur saccate, very short ( 1 mm.), wider basally than long. Anther apiculate, staminodes widely oblong, longer than the anther. Rostellum with its median tooth twice as large as the laterals, obtuse and grooved-gutter shaped in front.
Habitat:

In humid, bare spots, from the South-East: very common; flowering: June-July.
Distribution:

S. Madagascar