| 1 | Pedicels in fruit spreading, not thickened, 0.3-0.4 mm wide; sepals reflexed or spreading from fruiting aggregate |
| 1' | Pedicels in fruit reflexed or spreading, thickened, 1.2-5.5 mm wide; sepals appressed or erect around fruiting aggregate |
| 2 | Leaves and inflorescences submersed or floating; floating leaves with cordate, sagittate, or hastate base, basal lobes present |
| 2' | Leaves and inflorescences emerged or submersed, not floating; emerged leaves with acute to subcordate base, basal lobes absent |
