Lythraceae

Defining Characteristics

• Flowers typically with a prominent floral tube (hypanthium) — calyx tubular or urn-shaped with sepals at the rim
• Petals crinkled/wrinkled in bud (crumpled texture), inserted at the rim of the hypanthium
• Stems often square (4-angled) in cross-section
• Leaves usually opposite and simple, without stipules
• Fruit a capsule enclosed within the persistent floral tube
• Heterostyly (2–3 different style lengths within a species) common — promotes outcrossing

Notable Genera

• Lythrum (loosestrifes)
• Lagerstroemia (crape myrtles)
• Punica (pomegranate)
• Cuphea (cigar plants)
• Ammannia (ammannias — aquatic)
• Rotala (rotalas — aquatic)
• Didiplis (water hedge)

Notes

Includes several important aquarium plant genera (Rotala, Ammannia, Didiplis) — many of which develop intense red coloration under strong light, making them prized in aquascaping. Pomegranate (Punica granatum) is the most economically important species. Purple loosestrife (Lythrum salicaria) is a notorious invasive wetland plant in North America. Crape myrtles (Lagerstroemia) are major ornamental trees in warm climates. The square stems and crinkled petals are useful field diagnostics.