Key to the species of Sida sect. Sidae

1. Leaves distichous...................................................................................................................................................................... S.acuta

- Leaves not distichous .........................................................................................................................................................................2

2. Styles 5 ............................................................................................................................................................................ S.sivarajanii

- Styles 6–10 .........................................................................................................................................................................................3

3. Mericarp indehiscent ..........................................................................................................................................................................4

- Mericarp dehiscent at apex.................................................................................................................................................................6

4. Fruiting pedicels 2.0–3.0 cm long ......................................................................................................................................................5

- Fruiting pedicels 0.3–0.7 cm long ............................................................................................................................................ S. ovata

5. Awns exceeding the calyx, pubescent ................................................................................................................................ S.unicornis

- Awns completely included in the calyx, glabrous ......................................................................................................... S.rhomboidea

6. Pedicels not jointed.............................................................................................................................................................................7

- Pedicels jointed...................................................................................................................................................................................9

7. Leaves concolorous ............................................................................................................................................................. S.scabrida

- Leaves not concolorous ......................................................................................................................................................................8

8. Apex of mericarp beaked with a single muticous process, glabrous.............................................................................. S.rhombifolia

- Apex of mericarp with a pair of linear divergent awns, stellately hairy ......................................................................... S. keralensis

9. Leaves concolorous ...................................................................................................................................................... S.pradeepiana

- Leaves not conclorous ......................................................................................................................................................................10

10. Leaves near to the base of the stem always obovate, mericarp with a pair of short, stellately hairy mucro at apex .......... S.alnifolia

- Leaves otherwise, mericarp with a pair of short divergent glabrous awns...................................................................... S.subcordata