Onagraceae

Defining Characteristics

• Flowers typically 4-merous (4 sepals , 4 petals, 8 stamens ) — some genera 2-merous
• Inferior ovary — a key diagnostic character
• Floral tube (hypanthium) often elongated, extending above the ovary
• Fruit usually a loculicidal capsule , sometimes a berry or nut
• Seeds often with a tuft of hairs (coma) for wind dispersal (Epilobium)
• Many species associated with wet or disturbed habitats

Notable Genera

• Oenothera (evening primroses)
• Epilobium (willowherbs, fireweed)
• Ludwigia (water primroses, seedboxes — aquatic)
• Fuchsia (fuchsias)
• Clarkia (clarkias, farewell-to-spring)
• Circaea (enchanter's nightshade)

Notes

Ludwigia is the largest genus and the only one that is predominantly aquatic, with over 80 species of marshland and aquatic herbs — many are popular aquarium plants (L. palustris, L. repens, L. arcuata). Evening primroses (Oenothera) are named for their flowers that open in the evening for moth pollination. Fireweed (Epilobium/Chamerion angustifolium) is a classic colonizer of burned and disturbed ground. Fuchsias are major ornamentals with bird-pollinated pendulous flowers.