| Rubiaceae | ** |
Flagenium anomalum
| Wernham ex Nguembou, Sonké, Zapfack & Lejoly | Syst. & Geogr. Pl. 73: 254 | 2003 |
| Rubiaceae | |
Flagenium arboreum
| Wernham | J. Bot. 51: 12 | 1913 |
| Rubiaceae | |
Flagenium farafanganense
| Ruhsam & A.P. Davis | Bot. J. Linn. Soc. 155: 560–562, fig. 1 | 2007 |
| Rubiaceae | ** |
Flagenium farafanganensis
| Ruhsam & A.P. Davis | Bot. J. Linn. Soc. 155: 560 | 2007 |
| Rubiaceae | ** |
Flagenium kamerunense
| Mildbr. | Wiss. Ergebn. Zweit. Deut. Zentr.-Afr. Exped., Bot. 2: 63 | 1922 |
| Rubiaceae | |
Flagenium latifolium
| Wernham | J. Bot. 51: 12 | 1913 |
| Rubiaceae | |
Flagenium pedunculatum
| Ruhsam & A.P. Davis | Bot. J. Linn. Soc. 155: 562–563, fig. 1 | 2007 |
| Rubiaceae | |
Flagenium petrikense
| Ruhsam & A.P. Davis | Bot. J. Linn. Soc. 155: 563–565, fig. 2 | 2007 |
| Rubiaceae | ** |
Flagenium petrikensis
| Ruhsam & A.P. Davis | Bot. J. Linn. Soc. 155: 563 | 2007 |
| Rubiaceae | |
Flagenium setosum
| (A. Rich.) Wernham | Monogr. Sabicea 75 | 1914 |
| Rubiaceae | |
Flagenium triflorum
| (Vahl) Baill. | Hist. Pl. 7: 444 | 1880 |