| 1 | Stipules present (Paronychioideae) |
| 1' | Stipules absent |
| 2 | Leaves broad, ovate-orbicular |
| 2' | Leaves linear-narrowly elliptic |
| 3 | Styles 5 (or 3), free |
| 3' | Styles joined, at least at the base |
| 4 | Sepals carinate, green with scarious margin |
| 4' | Sepals not carinate, entirely scarious (except for a green midnerve in P. zollingeri). |
| 5 | Sepals free, petals short clawed (Alsinoideae) |
| 5' | Sepals connate, petals usually long-clawed (Caryophylloideae) |
| 6 | Styles 2 |
| 6' | Styles 2-5, flowers always hypogynous, if styles 2 then petals divided |
| 7 | Flowers perigynous, small, petals absent |
| 7' | Flowers hypogynous, petals usually present |
| 8 | Capsule opening with undivided valves in the same number as styles. |
| 8' | Capsule opening with more or less deeply divided teeth, so that the number is twice that of styles |
| 9 | Styles 2-3 |
| 9' | Styles 5 |
| 10 | Capsule ovoid, dehiscing by 5 bifid valves, styles alternating with the sepals, petals divided to the base |
| 10' | Capsule cylindrical, dehiscing by 10 equal or subequal teeth, styles opposite the sepals, petals undivided or divided halfway down |
| 11 | Calyx 5-winged, styles 2 |
| 11' | Calyx not winged, styles 2, 3, or 5 |
| 12 | Styles 3-5 |
| 12' | Styles 2 |
| 13 | Styles 3 (4-5), capsule-teeth twice as many as styles |
| 13' | Styles 5, capsule-teeth as many as styles |
| 14 | Calyx teeth with scarious commisures |
| 14' | Calyx teeth without scarious commisures |
| 15 | Epicalyx scales present |
| 15' | Epicalyx scales absent |
