Polystachya in Africa an Madagascar
Description:
Polystachya species are classified into thirteen sections. Apart from with sect. Polystachya which is pantropical, all sections are confined to Africa and Madagascar with two endemic to Madagascar and the Indian Ocean islands.
A key to the sections:
| 1 | Pseudobulbs 1-leaved | 2 |
| 1b | Pseudobulbs 2-to many-leaved | 4 |
| 2 | Leaf linear, grass-like; pseudobulbs clustered; rostel-lum elongate, beak-like | section Bicalcaratae |
| 2b | Leaf oblong, obovate, ovate or ligulate; pseudobulbs dustered or not; rostellum truncate or slightly notched | 3 |
| 3 | Rachis pubescent, pseudobulbs 2-noded | section Caleatae |
| 3b | Rachis glabrous; pseudobulbs many-noded | section Cultriformes |
| 4 | Leaves absent at the anthesis | 5 |
| 4b | Leaves present at the anthesis | 6 |
| 5 | Rachis covered with papery sheaths; lip longer than wide or as long as wide | section Steudnerae |
| 5b | Rachis not covered with papery sheaths; lip markedly wider than long | section Eurychilae |
| 6 | Stem reed-like, pseudobulbs absent, leafy in upper half; pseudobulbs absent | section Caulescentes |
| 6b | Pseudobulbs present, of different shape | 7 |
| 7 | Stems thickened into pseudobulbs after the anthesis; pseudobulbs disc-like, conical, ovate or cylindric | section Humiles |
| 7b | Stems thickened into pseudobulbs before the anthesis; pseudobulbs fusiform to conical | 8 |
| 8 | Mentum absent; lip with high, horn-like callus; column foot rudimentary; plants endemic to Madagascar | section Oreochares |
| 8b | Mentum present; lip with a fleshy callus if any; column foot prominent | 9 |
| 9 | Inflorescence dense and compact; flowers tiny to small, subglobose; rostellum elongate, ribbon-like or furculate | section Calluniflorae |
| 9b | Inflorescence not compact; flowers medium-sized, not globose; rostellum truncate or notched | 10 |
| 10 | Stems superposed | 11 |
| 10b | Stems not superposed | 12 |
| 11 | Terrestrial plant, bamboo-like; sepals 12-14 mm long; lip 8-13 mm long | section Dimorphocaules |
| 11b | Epiphytic plant; sepals 1-6 mm long or 20-25 mm long; lip 1.5-6 mm long or 15-18 mm long | section Superpositae |
| 12 | Flowers of dull colours; anther partitions obscure | section Polystachya |
| 12b | Flowers brightly coloured (orange, yellow, white, cream, pink or purple); anther partitions prominent; plants endemic to Madagascar, Comoros and Seychelles | section Pseudomonophyllae |
Unguiculabia Mytnik & Szlach. 5 species. see A key to the species of Unguiculabia
Disperanthoceros Mytnik & Szlach. = Polystachya anthoceros la Croix & P.J.Cribb
Szlachetkoella Mytnik Epiphorella Mytnik & Szlach. = Polystachya section Aporoidea Kränzlin
Isochilostachya Mytnik & Szlach.= Polystachya section Isochiloides
Dendrobianthe (Schltr.) Mytnik,= Polystachya section Dendrobianthe Schlechter
Neoburttia Mytnik, Szlach. & Baranow,= Polystachya longiscarpa Summerh.
Chelystachya Mytnik & Szlach.= Polystachya section Affines
Epiphorella Mytnik & Szlach.,= Polystachya section Elasticae
Reference:
A new revision of the subtribe Polystachyinae Schltr. (Orchidaceae). By Jonna Mytnik Ejsmont Ph.D. University of Gdansk • Department of Plant Taxonomy and Nature Conservation 2011
