Lythrum
5 species in Aust. (2 endemic); all states and territories
Herbs. Leaves opposite or alternate, sessile; stipules absent. Flowers regular, bisexual. Floral tube ribbed, enclosing the ovary. Sepals 4–6, very much shorter than the floral tube and alternating with 4–6 external appendages resembling sepals. Petals 4–6. Stamens as many, or twice as many, as the petals. Ovary superior, 2-locular; placentas axile; style capitate. Fruit an oblong capsule enclosed in the persistent floral tube, dehiscing at the summit.