Dendrosipanea

Delprete, Piero G., 2018, Two new species of the tribe Sipaneeae (Rubiaceae) from white-sand areas of Brazilian and Colombian Amazon, Phytotaxa 382 (1), pp. 125-135 : 129

Key to the species of Dendrosipanea

1. Leaf blades mostly round or broadly obtuse (rarely acute) at apex, primary and secondary veins impressed above and prominent below; inflorescence 3–7 × 2–3 cm including peduncle and flowers...................................................................................... D. revoluta

- Leaf blades obtuse to acute at apex, primary and secondary veins not impressed above and slightly prominent below; inflorescence 6–16 × 3–13 cm including peduncle and flowers.......................................................................................................................................2

2. Corollas 19 − 22.5 mm long; tube 11–14 mm long, 1.6–1.9 mm wide at base, 2 − 2.8 mm wide at mouth; lobes ovate to narrowly ovate, 7.5–8.5 × 4.5–4.8 mm, acute at apex ....................................................................................................................... D. prancei

- Corollas 27 − 30 mm long; tube 16–20 mm long, 2–2.5 mm wide at base, 3.5 − 4.5 mm wide at mouth; lobes oblong to ovate-oblong, 12–16 × 5–7.5 mm, obtuse to acute at apex ................................................................................................................. D. spigelioides