Lythraceae is a family of flowering plants that includes 28 genera and about 620 species of herbs, shrubs, and trees. The larger genera include Cuphea (275 spp.), Lagerstroemia (56), Nesaea (50), Rotala (45), and Lythrum (35). 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). Lythraceae has a worldwide distribution, with most species in the tropics, but ranging into temperate climate regions as well.
The family is named after the type genus, Lythrum, the loosestrifes (e.g. Lythrum salicaria purple loosestrife) and also includes henna (Lawsonia inermis). It now includes the pomegranate, formerly classed in a separate family Punicaceae. The family also includes the widely cultivated crape myrtle trees. Botanically, the leaves are usually in pairs (opposite), and the flower petals emerge from the rim of the calyx tube. The petals often appear crumpled.
Characteristics
Lythraceae species are most often herbs, and less often shrubs or trees; the shrubs and trees often have flaky bark. 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.
Leaves
The leaves generally have an opposite arrangement, but sometimes are whorled or alternate. They are simple with smooth margins and pinnate venation. or rarely inferior. The two to many carpels can be fused together (syncarpous), with two to numerous ovules in each locule, with axile placentation of the ovules.
Economic importance
Edible crops include the pomegranate (Punica granatum) and the water caltrop (Trapa bicornis or T. natans). The pomegranate is cultivated for the fleshy arils surrounding the seeds, and the water caltrop for its seeds. Henna (Lawsonia inermis) is cultivated for the dye of the same name, derived from its leaves.
Ornamentals are grown from a number of genera, including Cuphea, Lagerstroemia (crape myrtles), and Lythrum (loosestrifes).
Taxonomy
Within the order Myrtales, the family Lythraceae is most closely related to the Onagraceae, with the Combretaceae sister to both families. in five subfamilies:
Subfamily Lythroideae <small>de Jussieu ex Walker-Arnott, 1832</small> — (formerly Lythraceae sensu stricto)
- Adenaria
- Ammannia — (syn. Crenea , Hionanthera , and Nesaea )
- Capuronia
- Cuphea
- Decodon
- Didiplis
- Diplusodon
- Galpinia
- Ginoria — (syn. Haitia )
- Gyrosphragma
- Heimia
- Koehneria
- Lafoensia
- Lagerstroemia
- Lawsonia
- Lourtella
- Lythrum
- Pehria
- Pemphis
- Physocalymma
- Pleurophora
- Rotala
- Tetrataxis
- Woodfordia
Subfamily Punicoideae <small>(Horan. 1834) S. A. Graham, Thorne & Reveal 1998</small> — (syn. Punicaceae)
- Punica
Subfamily Sonneratioideae <small>(Engl. & Gilg 1924) S. A. Graham, Thorne & Reveal 1998</small>
Gallery
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Image:Lagerstroemia indica 0002.jpg|Crepe myrtle
Image:Lagerstroemia_indica-petals.jpg|Crepe myrtle flowers - the petals emerge from the calyx tube.
Image:Blutweiderich 0506112.jpg|Lythrum salicaria
Image:Cuphea ignea1.jpg|Cuphea ignea
Image:Cuphea nudicostata 3.jpg|Cuphea nudicostata
Image:Pomegranate flower and fruit.jpg|Pomegranate
File:Unidentified Rotala species W IMG_3730.jpg|Rotala species
</gallery>