Key to species in the F. sarmentosa complex

1. Acrophylls apex round; syconia 4 cm or larger in diameter................................................................................................. F. pumila

1. Acrophylls apex often caudiform to acute (round in F. muricata); syconia less than 3 cm in diameter............................................ 2

2. Leaf brown when dry; acrophylls abaxially seldom foveolate; syconia tuberculate more or less ..................................................... 3

2. Leaf not brown when dry; acrophylls abaxially foveolate or not (in some varieties of F. sarmentosa); syconia not tuberculate..... 4

3. Acrophylls less than 7 cm in length; peduncle (2–) 5–12 mm; syconia 6–8 mm in diameter ...................................... F. dinganensis

3. Acrophylls 7–26 cm in length; peduncle 2 mm to sessile; syconia 1–2 cm in diameter.................................................................... 5

4. Acrophylls 25 cm or larger in length; syconia and leaf covered by dense brown pubescent............................................ F. anserina

4. Acrophylls less than 20 cm in length; syconia and leaf covered by sparse pubescent to glabrous...................................................... ....................................................................................... F. sarmentosa and its allies (taxa in subclade f in Fig. 1 except F. pumila)

5. Acrophylls 13–26 cm in length, apex round, abaxial surface glabrous............................................................. F. muricata (sp. nov.)

5. Acrophylls 7–18 cm in length, apex acuminate to short caudiform, abaxial surface sparsely to densely tomentose........................ 6

6. Acrophylls 5–8 cm in width, basal vein basal vein up to 1/3 to 1/2 of lamina length; synocia 1.5–2 cm in diameter ........................ ........................................................................................................................................................................................... F. pubigera

6. Acrophylls 3–5 cm in width, basal vein basal vein up to 1/5 to 1/3 of lamina length; syconia often less than 1.5 mm in diameter... ................................................................................................................................................................................................ F. howii