AFRICAN

ORCHIDS

Microcoelia microglossa Summerh., Bull. Misc. Inform. Kew 1936: 231 (1936).
Description:
Stem up to 32 x 2-3 mm. Scale-leaves acuminate, with 5-7 (-9) nerves, up to 3.6 (-6.1) mm. Roots few, slender, variously spreading, ± twisting and with few branches distally, mostly loosely attached to the substrate, ± terete, smooth, up to 44 cm x 1-2 (-3) mm. Inflorescence(s) ± erect, spreading, up to 50 mm long, up to 4 simultaneously, usually dense, each with up to 10 flowers; peduncle short, up to 10 mm long; rachis indistinctly flexuose, terete, smooth; bracts sheating, acute to subacute, with 1-2 nerves, up to 2.0 mm long, brownish. Pedicel distinct, ± curved, terete, up to 5.5 mm long; ovary slightly curved, 1.9-2.6x0.8 mm. Flowers variously orientated, with the spur predominantly in a horizontal position, up to 11.1 mm long including ovary and pedicel, whitish with a brownish median band on the sepals. Glandular hairs sparsely scattered on rachis, basal part of sepals and at the apex of spur, slightly more on the ovary. Dorsal sepal hooded, ovate, acute to subacute, with 3 nerves, 2.6-3.0 x 1.4-2.5 mm. Lateral sepals asymmetric, slightly convex, ovate, ± acute to subapiculate, with 3 nerves, thickened along the central nerve, connate below the ovary, 3.6-3.7 x 2.3-3.0 mm. Petals ovate, acute, a slightly thickened single nerve, 2.3-2.5x1.5-1.6 mm. Labellum short, 3-lobed; mid-lobe ± triangular in outline, porrect to decurved, with 5 nerves, lateral nerves branched; side-lobes indistinct, erect, ± rectangular, on the side towards spur mouth strengthened with a fleshy, oblong, ± plateshaped thickening, 2.3-2.5x 1.6-2.1 mm, midlobe alone up to 1.6 mm long; spur long, slightly curved, cylindrical, tapering into a distinctly inflated apex, conical-shaped, 18.6-19.9 mm long, apical inflation 0.7-1.4 mm in diameter. Column short, truncate, 1.0-1.4 mm long, 1.3-1.4 mm high; androclinium with a prominent obtuse, transversely-elliptic stigmatic area, shallowly excavated, with a raised obtriangular central area; rostellum lobes, ± porrect, oblong, subacute, at the apex beset with a ± deltoidal membranous appendage on the lower side up to 0.3 mm long. Anther thick-walled, slightly bivalved dorsally, in side view ± hemispherical, with a truncate ± thickened apex, with an inside beset with a central mid-ridge and 2 small ridges on each side, 1.1-1.4 x 1.4— 1.6 mm. Pollinia subglobose, asymmetric, surface uneven, with ± distinct flattened areas; in side view ± orbicular, 500-670 x 500-590 µm in median section elliptic, up to 420 pm thick. Stipes large, broadly wedge-shaped, tapering to the viscidium, 0.8-1.1 x 0.56-0.66 mm; viscidium ovate, ± apiculate, convex, with a truncate base, 410-450 x 330-400 µm. Capsule large, ± fusiform, 20-22 x 5-8 mm; pedicel up to 7 mm long. Seeds fusiform to bottle-shaped, testa cells narrowly elongate (in a dry state), with small, loop-shaped to minutely club-shaped and with few ± hookshaped processes, terminal ends distinctly elongated, (430-)520-680x40-50 pm (20 dry seeds measured).
Habitat:
In dense lowland rain forest, occasionally in secondary forest. Epiphytic on understorey vegetation, often very loosely attached to the substrate. It is said to be able to reestablish itself in the undergrowth after the felling of large trees. Altitude. 470-1070 m.
Flowering period:
Later part of the dry season before the main rains.
Cultivation:
As given for the genus.
Notes:
Very similar superficially to Microcoelia caespitosa (Rolfe) Summerh. in Section Brachyglossa but the column is very short with the androclinium only gently sloping upwards while the rostellum and its associated structures (stipes and viscidium) are also short and broad. Another striking feature is the exceptionally long spur (nearly 2 cm. long) which is suddenly widened near the apex and then tapers to the apex itself.
Distribution:
Nigeria to Uganda
References:
WCSP (2017). 'World Checklist of Selected Plant Families. 03.03-2017; http://apps.kew.org/wcsp/
Images:
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