Auxopus macranthus Summerh., Kew Bull. 6: 467 (1951 publ. 1952).
Auxopus kamerunensis var. grandiflora Summerh., Bull. Misc. Inform. Kew 1936: 222 (1936).
Plant leafless, saprophytic. Rhizome up to 5 cm long and 0.8 cm in diameter, tuberoid, narrowly cylindrical, horizontal. Stem up to 30 cm tall, 0.07-0.09 cm in diameter, slender, more or less flexuous, glabrous, delicate, well-spaced from one another, Inflorescence 1.2-3 cm long, 15-25-flowered, dense. Flowers tubular, erect or spreading, yellowish brown or brown-orange. Flower bract 1-3 mm long, ovate-lanceolate, acuminate, membranous, delicate. Pedicel 2 mm long, twisted. Ovary 5 mm long, narrow cylindrical. Tepals thin, membranous. Dorsal sepal 7.5-8.5 mm long, 0.7 wide, linear-lanceolate, acute, single-nerved, connate with the lateral sepals to the half of its length. Petals 8 mm long, 0.8 wide, linear, obtuse at the apex, agglutinate to the sepals to half of their length. Lateral sepals 7-8 mm long, 1 mm wide, lanceolate, acute, cochleate and falcate at the apices, 3-nerved, joined together almost to their apices. Lip 6.5 mm long, 1.4-1.9 mm wide, narrow obovate in general outline, gradually attenuate towards the base, thin, membranous, indistinctly 3-lobed at the apex, midlobe cucullate, 3-nerved. Gynostemium 6.5-7.5 mm long. Column foot 1 mm long.
Humid, lowland, degraded forests with Monopetalanthus spp., Diospyros spp., Mapania spp., and Raphia regalis Becc.
Flowering from December-January.
This species is very similar in most respects to Auxopus kamerunensis Schltr., but has considerably larger flowers on a longer and more richly flowered rhachis. The lip is quite entire at the end and usually bluntly pointed, instead of more or less emarginate as in the other species. The species is clearly widespread in the equatorial African forest region. Auxopus seems to be sufficiently distinguished from Didymoplexis by the scarcely 2-lipped perianth and the entire ecallose lip, but the two genera are undoubtedly closely allied.
Not in cultivation
Ivory Coast, Ghana, Nigeria, Cameroon, the Democratic Republic of Congo (Zaire), Uganda.
Orchidaceae of West-central Africa, vol. 1, Gdansk University Press Gdansk 2010; Flora of West Tropical Africa, Vol 3, Part 1,; African Orchids: XX V. S. Summerhayes, Kew Bulletin, Vol. 6, No. 3 (1951), pp. 461-475; ORCHIDACEAE AFRICANAE: I. — Les Orchidées congolaises: caractères végétatifs et floraux, types biologiques, clef de détermination des genres sympodiaux, aperçu sur les genres R. TOURNAY, Bulletin de la Société Royale de Botanique de Belgique / Bulletin van de Koninklijke Belgische Botanische Vereniging, T. 87, Fasc. 1 (Avril 1955), pp. 57-79; Orchidaceae of Ivory Coast by Dariusz Szlachetko, 2008
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