Imerinaea madagascarica Schltr., Repert. Spec. Nov. Regni Veg. Beih. 33: 153 (1924).
Heterotypic Synonyms:

Phaius gibbosulus H.Perrier, Mém. Inst. Sci. Madagascar, Sér. B, Biol. Vég. 6: 262 (1955).

Plants 20-30 cm. tall; pseudobulbs unifoliate, closely set, roots villous. Leaves lanceolate-lingulate (10-17 x 1.5-1.8 cm.), acuminate, attenuate, gradually petiolate, the limbus thinner and papery. Inflorescence longly (20cm.) pedunculate; raceme loose to 4 cm. long, 2-4 flowered, flowers clear yellow; bracts half as long as the ovary, acute, one veined, finely villous on both sides. Sepals and petals nearly similar, oblanceolate-apiculate (13 x 2.5 mm.), slightly attenuate in the upper fifth from the base. Labellum horn shaped, widely obovate when spread flat (10 x 9 mm.), not lobed but with the center apical margin fringed pleated, provided basally with a thick, large, villous callus, keel like, elongated in front by a long keel, with another enlarged, rounded callus at the tip, verrucose; 9 veined, the 5 median simple, except apically where all are shortly bifurcated, the 4 laterals branching toward the outer margins. Column 8mm. long, straight, without lateral auricles, entirely pubescent-papillous. Anther (2 x .7 mm.) papillous, excised apically, elongated behind by a narrow black, helmet shaped, obtuse appendage; pollina 4, flat, ovoid, contoured, joined by a small common viscidium; staminodes forming an unobtrusive projection, with the men lobe projecting and spatulate apically, elongated behind to the clinandrium by a small, thick, reddish, villous keel on its back side. Stigmas at the apex of the column. Ovary (and pedicel) 8 mm. long.

On shady rocks, in mossy forests, from 1500 m alt.; flowering: December-March.

NE. & C. Madagascar

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Botanical Drawing / Herbarium
Photograph copyright Swiss Orchid Foundation at the Herbarium Jany Renz Image used with kind permission.