Polystachya sect. Dimorphocaules

Bidault, Ehoarn, Lowry Ii, Porter P. & Stévart, Tariq, 2016, Polystachya orophila (Orchidaceae, Polystachynae), a new species from tropical West Africa, and clarification on the nomenclature and taxonomy of P. microbambusa, Phytotaxa 260 (3), pp. 247-257 : 249

Key to morphologically similar species belonging to Polystachya sect. Dimorphocaules and sect. Polystachya

1. Pseudobulbs growing successively on top of each other, forming a developed, long and persistant stem (P. sect. Dimorphocaules ) .................................................................................................................................................................................. P. microbambusa

1’. Pseudobulbs growing from one side of the preceding ones, forming clusters of pseudobulbs (P. sect. Polystachya )......................2

2. Inflorescence branched......................................................................................................................................................................... ..................................... Polystachya odorata Lindley (1862: 130) subsp. trilepidis (Summerhayes 1949: 433) Stévart (2004: 227)

2’. Inflorescence unbranched...................................................................................................................................................................3

3. Leaf oblong; flowers green, up to 25 per inflorescence ........................................................... P. leonensis Reichenbach (1881: 112)

3’. Leaf linear or narrowly ovate; flowers yellow, no more than 10 per inflorescence...........................................................................4

4. Leaf narrowly ovate, 7–9 × 1.5–2 cm; lip 3 mm long; lateral sepals obliquely triangular; terrestrial or lithophytic in forest; Angola.......................................................................................................................................... P. angularis Reichenbach (1867: 114)

4’. Leaf linear, 5–18 (21) × 0.3–0.8 (1.4) cm; lip 10–12 mm long; lateral sepals narrowly triangular; lithopytic or epiphyte on Afrotrilepis pilosa root clusters, in savannah; Guinea and Sierra Leone...................................................................................... P. orophila