AFRICAN

ORCHIDS

Microcoelia bulbocalcarata L.Jonss., Symb. Bot. Upsal. 23: 121 (1981).
Description:
Stem short, up to 12 x 3 mm. Scale-leaves acuminate, with 7-8 nerves, up to 5.0 mm long. Roots few, long, ± pendulous, loosely attached to the substrate, distally sparsely branched, smooth, terete, up to 53 cm x 1.5-2.0 mm. Inflorescence(s) erect, spreading, up to 15 mm long, up to 4 simultaneously, ± dense, each with up to 6 flowers; peduncle short, up to 5 mm long; rachis flexuose, ± terete, smooth, greenish; bracts sheathing, ± acute, 1-nerved, up to 1.6 mm long; pedicel distinct, smooth, up to 5.3 mm long; ovary straight, up to 3.2 x 1.1 mm. Flowers ± horizontal, ascending or descending, up to 15.4 mm long including ovary and pedicel, whitish with a dark green patch on the lip centre; base of sepals dark green with the apex of dorsal sepal pale green; column and anther pale green. Glandular hairs ± densely covering the ovary, more concentrated in the furrows; sparsely on rachis and at base of tepals and spur. Dorsal sepal hooded, bilobed, elliptic, ± acute, subapiculate, with 3 sparsely branched nerves, 4.8-6.3 x 2.6-3.7 mm. Lateral sepals asymmetric, elliptic, acute, slightly convex, shortly connate at the base, with 3 ± branched nerves, thickened along the mid-nerve, 5.2-7.0 x 3.2 mm. Petals ± asymmetric, obovate to ovate, obtuse, slightly convex, with 1 branched nerve, 4.5-6.0 x 3.0-3.8 mm. Labellum oblong, acute; mid-lobe triangular, ± horizontal to decurved, with 3 main nerves; side-lobes indistinct, with a prominent rounded ridge-like thickening on each side of spur moth, 4.2-5.0 x 2.6-3.7 mm. Spur long, ± cylindrical, ± descending vertically, inflated, tapering into a bulbous apical inflation, apex ± incurved, 7.7-10.5 mm long, apical inflation 1.8 x2.5 mm. Column short, truncate, slightly recurved, 1.0-1.3 mm long, up to 1.5 mm high; androclinium shallowly excavated, with a central thickening; rostellum lobes ± horizontal, oblong, acute, with a rectangular membranous process in between, up to 1.3 mm long. Anther ± hemispherical, bivalvate dorsally, in backview cordate, tapering into a triangular prolongation, apex acute, reflexed, 2.0-2.4 x 1.6 mm. Pollinia large, ellipsoid, asymmetric; in side view ± semielliptic to semiovate, 910-1000 x 580-620 in median section elliptic to obovate, up to 630µm thick. Stipes spathulate, apically triangular-shaped, ± sigmoid, 1.4-1.6 x 0.5-0.6 mm (at the apex), brownish; viscidium rounded oblong, convex, tapering into a truncate base, 0.8-1.0 x 0.50-0.55 mm, brownish.
Habitat:
Dense upland forest. Epiphytic on the forest undergrowth. Altitude. 1680-1950 m.
Flowering period:
Recorded from the late rainy season.
Cultivation:
As given for the genus, cool growing epiphyte.
Distribution:
Príncipe to Gabon, SW. Uganda to W. Rwanda
References:
African Orchids in the Wild and Cultivation Lacroix 1997; WCSP (2017). 'World Checklist of Selected Plant Families. 03.03-2017; http://apps.kew.org/wcsp/
Images:
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In culture
microcoelia bulbocalcarata
Photograph©Steve Beckendorf. Image used with kind permission.