Key to the genera of the Acmanthera clade
1. Each lateral inflorescence reduced to a sessile or subsessile fascicle of 2–6 flowers; corolla radially symmetrical or nearly so, the posterior petal hardly different from the 4 lateral petals; stipules up to 0.8 cm long.

1. Each lateral inflorescence an elongated many-flowered spike or pseudoraceme; corolla bilaterally symmetrical, the posterior petal notably different from the 4 lateral petals; stipules 1.5–11 cm long.

2. Inflorescence a spike, i.e., each flower sessile, raised on neither a peduncle nor a pedicel; sepals all eglandular; anthers unwinged, dehiscing by oblique apical or subapical pores; 2 stipules on inner face of each petiole connate, persistent while growth proceeds but mostly deciduous before the subtending leaf.

2. Inflorescence a pseudoraceme, i.e., each flower pedicellate;  sepals all biglandular; anthers bearing a longitudinal wing on each of the outer locules, dehiscing by longitudinal slits; 4 stipules at each node longitudinally pressed together or connate to form a single sheath, deciduous as growth occurs.

Pterandra
Coleostachys
Acmanthera