Lythraceae
[4] It also includes the members of the former families of the pomegranate (Punica granatum, formerly in Punicaceae) and of the water caltrop (Trapa natans, formerly in Trapaceae).[5] Traits shared by species within the Lythraceae that distinguish them from belonging to other plant families are the petals being crumpled in the bud and the many-layered outer integument of the seed.[4] Heterostyly – the presence of two (distylous) or three (tristylous) distinct flower morphs within a species differing in the lengths of the pistil and stamens – is common within the Lythraceae.[4][5] The oldest fossils of the family are pollen from the Late Cretaceous (Campanian) of Wyoming in western North America, around 82 to 81 million years old.Ornamentals are grown from a number of genera, including Cuphea, Lagerstroemia (crape myrtles), and Lythrum (loosestrifes).[4] Purple loosestrife (Lythrum salicaria) is an invasive exotic weed of wetlands throughout Canada and the United States.