Oenothera
13 species naturalized in Aust.; all states and territories
Herbs with alternate leaves. Flowers solitary in the axils of the upper leaves forming a leafy spike. Sepals 4, deflexed. Petals 4, obovate, spreading. Tubular free part of the floral tube extending far above the ovary and falling off with the sepals etc. Stamens 8. Ovary 4-locular. Capsule 4-valved, opening loculicidally from the summit.