Clerodendrum

Satthaphorn, Jiratthi, Paton, Alan J. & Leeratiwong, Charan, 2021, Clerodendrum angustipetalum, a new species of Clerodendrum (Lamiaceae) from Thailand, Phytotaxa 491 (2), pp. 177-183 : 182

Key to species of pendulous inflorescence Clerodendrum in southern Thailand

1 Inflorescence compacted, corymb-thyrsoid................................................................................................... Clerodendrum deflexum

- Inflorescence elongate thyrsoid..........................................................................................................................................................2

2 Calyx lobes broadly ovate-triangular, more than 3 mm wide ...................................................................... Clerodendrum umbratile

- Calyx lobes narrowly triangular, less than 3 mm wide ......................................................................................................................3

3 Leaf membranaceous; calyx tube up to 2 mm long; calyx lobes 4–6 mm long; corolla tube 9–13 mm long; corolla lobes 10–14 by 6.5–10 mm; stamens up to 4 cm long................................................................................................................ Clerodendrum nutans

- Leaf subcoriaceous; calyx tube more than 2 mm long; calyx lobes 7–8 mm long; corolla tube 16–18 mm long; corolla lobes 17–22 by 2.8–4 mm; stamens more than 4 cm long....................................................................................... Clerodendrum angustipetalum