The Manual of the Botany of the Northern United States / Including the District East of the Mississippi and North of North Carolina and Tennessee

by Asa Gray

[+] Styles opposite the sepals, or, when fewer, opposite those which are exterior in the bud.

[++] Pod short, splitting into as many valves as styles; valves often bifid or 2-parted.

6. Arenaria. Petals entire. Styles usually 3. Valves of the pod entire, bifid or 2-parted.

7. Stellaria. Petals 2-cleft or none. Styles usually 3. Valves bifid or 2-parted.

[++][++] Pod cylindrical, dehiscent by twice as many equal teeth as styles.

8. Holosteum. Petals denticulate or notched. Styles usually 3. Seeds fixed by the face.

9. Cerastium. Petals notched or 2-cleft. Styles 5 or 4. Seeds fixed edgewise.

[+][+] Styles alternate with the sepals. Stamens as many, or twice as many.

10. Sagina. Petals 4 or 5, entire, or none. Styles 4 or 5. Pod short, 4–5-valved.

[*][*] Stipules present. Pod short.