| | 1. Sepals acute to acuminate, generally > petals; flowers generally 2 per leaf pair; follicles 1–2-seeded; terrestrial |
| |
| | 2. Sepals generally 4, erect; flowers sessile or pedicelled |
| C. connata |
| | 2' Sepals generally 3, tip often outcurved; flowers subsessile |
| C. tillaea |
| | 1' Sepals rounded to obtuse, << petals; flower 1 per leaf pair; follicles 6–17-seeded; aquatic, later generally stranded in dry ponds |
| |
| | 3. Follicles oblong, subtruncate; suture erect, straight, abruptly outcurved in upper 1/4 |
| C. aquatica |
| | 3' Follicles lanceolate, obliquely acute; suture outcurved from near middle |
| C. solieri
|