Corycium nigrescens Sond., Linnaea 19: 110 (1846).
Pterygodium nigrescens (Sond.) Schltr., Bull. Herb. Boissier 6: 847 (1898).
A terrestrial herb, 20 to 60 cm tall, drying black; tubers ellipsoid; roots slender, elongate, arising from base of stem. Stem terete, leafy, covered by imbricate sheathing leaf bases. Leaves 5-7, lanceolate, acuminate, longest in middle or upper part of stem, 10-20 x 1- 1-9 cm, sheathing at base, lowermost reduced to sheaths. Inflorescence a cylindrical spike, 5- 12 cm long, densely many-flowered; bracts lanceolate, acuminate, up to 2 - 5 cm long, usually overtopping the flowers. Flowers subglobose, dark maroon or dark brown turning black; ovary 0, 7-0, 8 cm long, glabrous. Dorsal sepal strongly concave, hooded, subcircular, obtuse, 0 3-0 4 cm long and wide, somewhat pustulate on outer surface, rather thick textured, 5-veined. Lateral sepals deflexed, somewhat concave, obliquely ovate- elliptic, obtuse, 0,45-0,55 x 0,3-0-45 cm, thin-textured, 3-veined. Petals deeply concave, enclosing the lateral lobes of the lip appendage, adnate to the dorsal sepal, transversely elliptic to subcircular, with a very obliquely placed, shortly apiculate apex, similar in texture to dorsal sepal, pustulate on outer surface. Lip complex, about 0 -5 x 0 -75 cm when flattened; appendage with two large and strongly incurved lateral lobes which are recurved strongly at the apex, about 0-3 cm long; lip blade oblong-obovate, obtuse to rounded at the apex, 0, 25 x 0 2 cm. Column adnate to lip appendage.
The habitat is predominantly summer rainfall grassland to elevations of 3000 m, often mountainous terrain.
Happens from mid-spring to early summer (Liltved and Johnson, 2012; Pooley, 1998).
S. Tanzania (Kitulo Plateau), S. Africa
Encyclopedia of Cultivated Orchids Hawkes 1965; Wild Orchids of Southern Africa Stewart, Linder, Schelpe & Hall 1982; Field Guide to the Orchids of Northern South Africa and Swaziland McMurty, Grobler, Grobler & Burns 2008
Click on each image to see a larger version.