Habenaria retinervis Summerh., Kew Bull. 16: 291 (1962).
Homotypic Synonyms:
Bilabrella retinervis (Summerh.) Szlach. & Kras-Lap., Richardiana 3: 142 (2003).
Description:
A terrestrial herb 3.5-8.5 dm. high, glabrous except for the roots and petals. Tubers globose, ovoid or ellipsoid, 1-3 cm. long, 1-1.5 cm. in diameter, rather densely tomentose. Stem erect, rather stout, leafy throughout its length. Leaves 7-11, the lowermost 2-3 reduced to sheaths, ± recurved, white with green reticulate veins, the 4-5 middle ones suberect, lanceolate to elliptical, the largest 5-14 cm. long and 1-3 cm. broad, the upper ones much smaller, adpressed to the stem, similar to the bracts. Inflorescence 10-27 cm. long, 4-5.5 cm. in diameter, rather loosely 8-28-flowered. Bracts lanceolate, acuminate, 1-2.5 cm. long, shorter than the pedicel with ovary. Flowers curved outwards, green with lip and petals whitish; ovary with pedicel curved, 2-3 cm. long. Dorsal sepal reflexed, narrowly elliptical, obtuse, convex, ± 6 mm. long and 3 mm. broad; laterals deflexed, obliquely obovate, apiculum lateral, 7-9.5 mm. long, 4.5-6.5 mm. broad. Petals bipartite nearly to the base; posterior (upper) lobe recurved, linear or ligulate-linear, denticulate towards apex, 5-6.5 mm. long, 1 mm. broad, ciliolate; anterior petal-lobe projecting forwards, lanceolate, acute, 8.5-11.5 mm. long, 1-2.5 mm. broad. Lip deflexed, tripartite nearly to the base; middle lobe ± incurved, linear, 11-13.5 mm. long, scarcely 1 mm. broad; side lobes narrowly lanceolate, acute, 7.5-11 mm. long, a little broader than the middle lobe; spur ± parallel to the ovary, somewhat swollen in the apical half, 2.5-3 cm. long. Anther 2-3 mm. high, loculi reclinate, canals porrect or slightly incurved, nearly 4 mm. long; stigmas porrect, swollen and truncate at very apex, ± 4 mm. long, rostellum triangular, acute, ± 2 mm. long.
Habitat:
Brachystegia woodland, often in grassy clearings and on forest margins 1300–1740 m.
Notes:
This species resembles in some respects Habenaria compta. Both differ in the length of posterior petals lobe, stigmaphores and rostellophores. In Habenaria retinervis posterior petals lobes are 9.5-11.5 mm long, and stigmaphores and rostellophores 4 mm long. In Habenaria compta posterior petal lobes are 5.5-6 mm long, and stigmaphores and rostellophores only 2-3.3 mm long.
Cultivation:
As described for the genus, cool growing terrestrial.
Distribution:
The Democratic Republic of Congo (Zaire), Tanzania, Angola, Zambia, Malawi.
References:
Orchidaceae of West-central Africa, vol. 1, Gdansk University Press Gdansk 2010; Flora of Tropical East Africa Part 1 Summerhayes 1968; The Orchids of South Central Africa Williamson 1977; Flora Zambesiaca Volume 11 Part one Pope 1998; African Orchids: XXVIII V. S. Summerhayes, Kew Bulletin, Vol. 16, No. 2 (1962), pp. 253-314
Images:
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Habitat/In situ	Habitat/In situ	Habitat/In situ	Habitat/In situ
Photograph© Nicholas Case Wightman Image used with kind permission.	Photograph© Nicholas Case Wightman Image used with kind permission.	Photograph© Nicholas Case Wightman Image used with kind permission.	Photograph© Nicholas Case Wightman Image used with kind permission.