Microcoelia megalorrhiza (Rchb.f.) Summerh., Bot. Mus. Leafl. 11: 158 (1943).
Angraecum megalorrhizum Rchb.f., Otia Bot. Hamburg.: 117 (1881).
Angorchis megalorrhiza (Rchb.f.) Kuntze, Revis. Gen. Pl. 2: 651 (1891).
Epidorchis megalorrhiza (Rchb.f.) Kuntze, Revis. Gen. Pl. 2: 660 (1891).
Gussonea megalorrhiza (Rchb.f.) Schltr., Beih. Bot. Centralbl. 36(2): 93 (1918).
Stem up to 35x3-4.5 mm. Scale-leaves acuminate to rostrate, with 6-7 nerves, up to 6.8 mm long. Roots long, mostly few, variously spreading and twisting, often branched distally, ± loosely attached to the substrate, ± terete, distinctly verrucose, up to 30(—50) cm x 1.5-2.5(3.0) mm, when living having a silvery yellow brown lustre in a ± dry state. Inflorescence(s) ± erect or pendulous, spreading, up to 130 mm long, up to 10 simultaneously, usually ± sparse, each with up to 20 flowers; peduncle short, up to 10 mm long; rachis straight to indistinctly flexuose, ± terete and slightly excavated; bracts sheathing, acute, with 0-3 nerves, 2.0(-2.6) mm long, transparent yellow brown. Pedicel short, ± geniculate, up to 2.0 mm long, fading into salmon pink; ovary straight, 3.0-3.9x0.5-0.7 mm, fading into salmon pink. Flowers ± horizontal, up to 12 mm long including ovary and pedicel, whitish, basal part of the tepals and apical part of the spur fading into salmon pink. Glandular hairs ± dense, scattered on pedicel and ovary, sparsely on rachis, bracts and at the base of the tepals. Dorsal sepal narrowly elliptic to narrowly oblong, acuminate, with a slightly bulging area, 3-nerved, 5.7-7.0 x1.8-2.4 mm. Lateral sepals slightly asymmetric, narrowly oblong, acuminate, 3-nerved, 6.6-8.7 x 1.6—2.4 mm. Petals narrowly elliptic, acuminate, apically ± erose, 5.6-7.4 x 1.8-2.4 mm. Labellum large, 3-lobed; mid-lobe subspathulate, deeply concave, ovate, acuminate, apically ± erose, 5-nerved, lateral nerves with branches; side-lobes narrowly oblong, thickened towards the spur mouth, 6.5-8.1 x 2.2-3.5 mm; spur cylindrical, ± semicircularly curved, tapering into a narrowly conical-shaped obtuse apex, 6.2-7.5x0.7- 1.0 mm, along curve up to c. 10 mm long. Column elongated, slightly recurved, with a central trigonal pillar-like thickening, 1.8-2.7 mm long, 1.0-1.4 mm high; androclinium shallowly excavated, with an indistinct mid-ridge; rostellum lobes long, ± perpendicular, rounded-truncate, up to 1.1 mm long, each up to 0.6 mm wide. Anther ± narrowly triangular in outline; in sideview bivalvate and ± flattened dorsally, tapering into a channelled ± geniculate, narrowly obtuse apex, 2.1-2.7 x c. 1.0 mm. Pollinia asymmetric, 500 – 600 x 500 - 550 µm; in median section ± elliptic, up to 300 µm. Stipes long, indistinctly sigmoid, channelled, with a head-like apex, tapering into a flattened, very narrow base, 1.8-2.6 mm long, 0.5-0.7 mm wide apically; viscidium minute, elliptic to obovate, membranous, 0.3-0.5 x 0.09-0.13 mm. Capsule long, straight, narrowly cylindric to narrowly ellipsoid, distinctly ribbed, 15-24x4-7 mm; pedicel short, up to 3.0 mm long. Seeds fusiform, testa cells narrowly elongate (in a dry state), with ± club-shaped and hook-shaped processes; anticlinal walls ± sulcate with finer striations, or narrowly grooved, terminal ends distinctly elongated, (470-)610-790 (-920) x 35-70 µm (65 dry seeds measured).
Dry woodland, usually on finer branches in the crowns of large trees. Altitude, c. 10-550 m.
During the late rainy season.
Easily distinguished by the verrucose roots. The lip lamina is narrower than in Microcoelia koehleri (Schltr.) Summerh.,the rostellum lobes are more acute and the viseidium is shorter and broader.
As for the genus, in fairly good light, at intermediate to warm tem peratures. Although this species is rare in the wild, it seems to grow well in cultivation.
Kenya to Malawi
Orchids of Kenya Stewart 1996; A Monograph of the Genus Microcoelia [Orchidaceae] Jonsson 1981; Malawi Orchids La Croix 1983; Flora of Tropical East Africa Orchidaceae Part 3 Cribb 1989; Orchids of Kenya Stewart & Campbell 1996; Flora Zambesiaca Vol 11 Part 2 Pope 1998; AOS Bulletin Vol 71 No 7 2002; AOS Bulletin Vol 72 No 3 2003; Angraecoid Orchids Stewart, Hermans and Campbell 2006; WCSP (2017). 'World Checklist of Selected Plant Families. 03.03-2017; http://apps.kew.org/wcsp/
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