| Biology : |
Epiphytic or lithophytic dwarf herb to 5 cm tall, pubescent; stems clustered, simple, pseudobulbous at base; pseudobulbs in chains or mats, ovoid, 1,5x0,8 cm, covered below with sheaths; leaves 2, linear, grass-like, c. 3,5x0,3 cm, deciduous in dry season; inflorescence terminal, simple, 1,5-5 cm long, 5-15-flowered, arising from leafless pseudobulbs; flowers pale lilac, lip white with brownish central line, pubescent outside, primrose-scented; bracts 2 mm long; pedicel and ovary 2-3 mm long; dorsal sepal ovate, 4-5x2-3 mm; laterals obliquely ovate, 5x3 mm; mentum (spur) rounded, 2-3 mm high; petals oblanceolate, 4-5x2 mm, apiculate; lip elliptic, 4x2,5 mm, entire, recurved, edges undulate; with a farinaceous-papillose disc. |
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| Ecology : |
Woodland in high rainfall areas; moist Brachystegia woodland; evergreen forest; riverine forest; on trees and mossy (granite) rocks; on lower branches of Brachystegia spiciformis; 900-2150 m alt. |
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Attractive species. “Vegetatively, almost identical to Polystachya brassii; the two species are virtually impossible to tell apart when not in flower” (I. & E. la Croix, 1997: 288). Both occur in similar habitats, occasionally on the same tree, but P. greatrexii has a lower altitude range and is much less common (Fl. Zambes. 11/2: 334, 1998). P. greatrexii can be distinguished in flower from P. brassii by the recurved, entire, frilly-edged lip (I. la Croix & al., 1991: 220). |
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