AFRICAN

ORCHIDS

Microcoelia stolzii (Schltr.) Summerh., Bot. Mus. Leafl. 11: 149 (1943).
Homotypic Synonyms:
Gussonea stolzii Schltr., Bot. Jahrb. Syst. 53: 596 (1915).
Heterotypic Synonyms:
Microcoelia ericosma Summerh., Bot. Mus. Leafl. 11: 251 (1945).
Description:
Stem up to 45 x 1.5—2(—3) mm. Scale-leaves acuminate, with 4—6(—7) nerves, up to 4.0-4.5 mm long. Roots many, slender, variously spreading, densely crowded, often characteristically twisted, with few branches or not, mostly ± loosely attached to the substrate, ± terete, smooth, up to 30(—50) cm x 0.5-1.5(-3) mm, when living having a silvery greenish blue-grey lustre in a ± dry state. Inflorescence(s) ± erect or pendulous, spreading, up to 120 mm long, up to 5(—15) simultaneously, usually dense, each with up to 40 flowers; peduncle short, up to 10 mm long; rachis ± straight to indistinctly flexuose, ± furrowed, (citrine); bracts not sheathing, ovate, acute, indistinctly 1-nerved, up to 2.0 mm long, (transparent russet). Pedicel minute, up to 2.0 mm long, (olive-buff of orange-citrine); ovary slightly curved, distinctly furrowed, (0.8—) 1.1—2.1(—3.1) x 0.3—0.7(— 1.0) mm. (olive-buff) with the furrows (vinaceous-rufous). Flowers ± horizontal, up to 9.4 mm long including ovary and pedicel; tepals pure white; spur whitish, apex ± darkish green, orange-brown at the very tip; anther yellow-brown; column light green. Glandular hairs very sparsely present, in general seen on rachis, base of bracts and tepals, ± concentrated at the base of spur and in the furrows of the ovary. Tepals ± similar, slightly convex, obovate to ovate, obtuse to subacute, ± apiculate, with a single ± thickened nerve. Dorsal sepal ( 1.8—)2.3—3.4(—3.9)x(0.8—) 1.0—1.6(—2.0) mm. Lateral sepals 2.0-3.5(-4.3) x (0.8-)1.0-l.5 (-1.9) mm. Petals (1.7-)2.3-3.3(-3.7)x(0.7-) 1.0—1.5(—1.7) mm. Labellum pandurate; midlobe narrowly obovate to ovate, obtuse to subacute, ± folded with 3 nerves; side-lobes rounded; ( 1.6—)2.0—3.2(—4.1 ) x (0.6—) 1.0—1.6(—2.0) mm; spur ± conical, tapering into a variously pointed cylindrical obtuse apex, slightly to markedly incurved or when undeveloped pointing backwards; ( 1.1—) 1.4—2.5(—3.4) mm long, along curve up to 3.5 mm, up to 0.6 mm in diameter apically, pure white at the base, apically fading into (dark citrine and at the very apex (orange-citrine). Column short, truncate, outer sides ± convex, 0.3-0.7(-1.0) mm long, (0.3-)0.6-l .0(-l .2) mm high, (lumière green to dull green-yellow); androclinium shallowly excavated, with a small hump in the centre; rostellum lobes ± inflexed, pendant or slightly protruding, ± rectangular, (0.16-)0.20-0.30 mm long, whitish, stigmatic area with a dark greenish blotch. Anther hemispherical in side view, frontally ± flattened, tapering into a short broadly truncate apex, 0.7-1.0(-1.2) x 0.6-0.9 mm (ochraceous yellow), apical rim whitish. Pollinia subglobose, asymmetric; in side view ± obovate to elliptic, (310-) 370-475(-560) x (300-)325-400(-450) µm in median section ± elliptic, slightly oblique, up to 200-250 µm thick, (wax yellow). Stipes ligulate, broadly spathulate and distinctly convexed apically, sigmoid, (300-)340-480 (-610) µm long, at the apex (100-1120-160 (-190) µm wide, transparent; viscidium ± quadrangular, rounded distally, (100-)180-280(-310)x (80-) 150-290 (-340) µm, membranous. Capsule ellipsoid to obovoid, 5-7 x (2-)3-4 mm; pedicel distinct, up to 2.0 mm long. Seeds bottle-shaped to ± cylindrical or fusiform, testa cells narrowly elongate (in a dry state), with ± club-shaped and more sparsely with hook-shaped processes; anticlinal walls ± sulcate, with finer striations and with slightly protruding terminal ends, (340-)370-440 (—470)x 60-90 µm. Scent distinct, fresh and tastable, a little pungent, ± similar to the smell of heather.
Habitat:
Mainly in upland rain forest and riverine forest extending up to mountain forest, locally also in the transitional zone to woodland, and occasionally in plantations and secondary vegetation. Epiphytic on smaller branches and trunks, usually of understorey trees and bushes in ± shady conditions. Altitude. 760-2450 m.
Flowering period:
Recorded from the beginning of the late rainy season, proceeding to about the middle of it.
Notes:
This, like Microcoelia smithii (Rolfe) Summerh., is a close ally of Microcoelia globulosa (Hochst.) L.Jonss., which they appear to replace in Tanganyika Territory. Microcoelia stolzii is characterised by the spur which is only about half the length of the narrow acute lip and is markedly incurved. There are, however, specimens in the Kew Herbarium from Kenya Colony in which a relatively short incurved spur is associated with the broader lip and perianth segments of typical Microcoelia globulosa (Hochst.) L. Jonss. There is some evidence that these three species should more correctly be treated as variants of one species with which, perhaps, M.conica (Schltr.) Summerh. should also be associated.
Cultivation:
As given for the genus, but in moderately heavy shade.
Distribution:
Kenya to S. Trop. Africa
References:

The Orchids of South Central Africa Williamson 1977; A Monograph of the Genus Microcoelia [Orchidaceae] Jonsson 1981; Flora of Tropical East Africa Orchidaceae Part 3 Cribb 1989; Orchids of Kenya Stewart 1996; African Orchids in the Wild and Cultivation La Croix 1997; Flora Zambesiaca Vol 11 Part 2 Pope 1998; AOS Bulletin Vol 72 No 3 2003; Angraecoid Orchids Stewart, Hermans and Campbell 2006; Orchid Digest Vol 72 No 3 2008; WCSP (2017). 'World Checklist of Selected Plant Families. 03.03-2017; http://apps.kew.org/wcsp/
Images:
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Habitat/In situ Habitat/In situ Habitat/In situ
microcoelia stolzii microcoelia stolzii close Microcoelia stolzii 02
Photograph©Bart Wursten. Image used with kind permission. Photograph©Backmann. Swiss Orchid Foundation at the Herbarium Jany Renz Image used with kind permission. Photograph© Lourens Grobler. Image used with kind permission.