Key to Genera of Thunbergioideae

1a. Fruit fleshy and indehiscent (drupe); ovules 2; seeds 1 or 2.......................... 2

1b. Fruit woody and dehiscent (capsule); ovules 4; seeds up to 4......................... 3

2a. Mature ovary with 1 fertile locule (other locule rudimentary or aborted); drupe 1-seeded; pollen (4–) 5–6-colpate, colpi short (brevicolpate)............................... Mendoncia

2b. Mature ovary with 2 fertile locules; drupe 2-seeded; pollen (fide Raj 1961) 3(–4)-colpate, colpi elongate........................................................ Anomacanthus

3a. Stigma ± equally 2-lobed, each lobe again divided into 2 unequal lobes; pollen 7–9-lobate and colpate.............................................................. Meyenia

3b. Stigma funnelform to ± capitate or equally to unequally 2-lobed; pollen spiraperturate and unlobed................................................................... 4

4a. Anthers opening by longitudinal slits.................................... Thunbergia

4b. Anthers opening by apical slits or pores................................. Pseudocalyx