Satyrium carsonii Rolfe in D.Oliver & auct. suc. (eds.), Fl. Trop. Afr. 7: 265 (1898).
Satyrium leucanthum Schltr., Bot. Jahrb. Syst. 53: 525 (1915).
Satyrium nigericum Hutch., Bull. Misc. Inform. Kew 1921: 402 (1921).
A terrestrial herb 2.5-6.5 dm. high, glabrous except for the roots; tubers ovoid or narrowly ellipsoid, 1-3 cm. long, ± 1 cm. in diameter, tomentose; roots flexuous, slender, pubescent. Stem erect, terete, with 2 basal leaves and several distant sheaths. Two basal leaves subopposite, broadly ovate to reniform, adpressed to the ground, 1.5-6 cm. long, 1-9.5 cm. broad; sheathing leaves 3-5, scattered along the stem, lanceolate, 2-6-5 cm. long, 1-2 cm. broad. Inflorescence rather dense, 4-15 cm. long, 3-5 cm. in diameter, 3-18-flowered; bracts at first erect, later reflexed, lanceolate, 1.5-3 cm. long. Flowers spreading, white; pedicel with ovary straight, ± I cm. long. Sepals ± deflexed, united shortly at the base to the petals and lip; intermediate sepal oblanceolate or oblong, obtuse, 7.5-17 mm. long, 3-4 mm. broad; laterals obliquely oblanceolate, rounded at apex, 9.5-19 mm. long, 3-7 mm. broad. Petals oblanceolate, rounded at apex, 8-15 mm. long, 2.5-5 mm. broad; all tepals several-nerved. Lip erect, very convex and almost hooded, with a broad mouth and a projecting ± curved-back apex, 9-16.5 mm. long and ± as broad when spread out, 2-spurred at the base; spurs parallel to the ovary, ± curved, tapering from a broad base, 6-14 mm. long. Column ± enclosed in the lip, bow-shaped towards the back, 4-7 mm. high, the stalk thick, curved; anther-loculi horizontal, within the bend of the column; stigma semi-orbicular, 2-3 mm. high and 3-4 mm. broad, rostellum side lobes short, triangular, the middle lobe much larger, projecting downwards with apical part hooked upwards, ovate, acute.
Mixed and Brachystegia woodlands, dambo edges, grassy savanna, humid savanna.
As given for the genus, warm to cold growing terrestrial.
There is some variation in flower-size, plants from West Africa, Kenya and Tanzania having on the whole slightly smaller flowers than those from Zambia, but there is no sharp demarcation between the flower-sizes. There is also considerable variation in the length of the spurs but these are almost always distinctly shorter than the labellum itself. The species as here understood has a range from Nigeria eastwards to Kenya and southward to Malawi and Zambia. It may be distinguished from both Satyrium aethiopicum Summerh. and Satyrium kitimboense Kraenzl. by its shorter and more conically tapering spurs.
Nigeria, Cameroon, the Democratic Republic of Congo (Zaire), Uganda, Rwanda, Burundi, Kenya, Tanzania, Zambia, Malawi. Alt. 800-2100 m.
Orchidaceae of West-central Africa, vol. 1, Gdansk University Press Gdansk 2010; Flora of Tropical East Africa Orchidaceae Part 1 Summerhayes 1968; The Orchids of South Central Africa Williamson 1977; Flora Zambesiaca Vol. 11 Orchidaceae Part 1 Pope 1995; Orchids of Kenya Stewart & Campbell 1996
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