Caryophyllaceae (Pink family)
Opposite leaves and a swollen node as on this Dianthus deltoides (Maiden pink).
leaves opposite
leaves opposite
swollen nodes
swollen nodes
notches in flower petals
notches in flower petals
superior ovary
superior ovary
5 or 5+5 stamen
5 or 5+5 stamen
fruit capsule
fruit capsule
Notched petals and 5 + 5 stamens as in this Arenaria fendleri (Fendler's sandwort),