| Lythraceae | |
|---|---|
 | |
| Lythrum salicaria | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Myrtales |
| Family: | Lythraceae J.St.-Hil.[2] |
| Genera | |
28 – see text | |
| Synonyms[3] | |
| |
Lythraceae is a family offlowering plants that includes 28genera and about 620 species of herbs, shrubs, and trees.[4] The larger genera includeCuphea (275 spp.),Lagerstroemia (56),Nesaea (50),Rotala (45), andLythrum (35).[5] It also includes the members of the former families of thepomegranate (Punica granatum, formerly inPunicaceae) and of thewater caltrop (Trapa natans, formerly inTrapaceae). 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 salicariapurple loosestrife) and also includeshenna (Lawsonia inermis). It now includes thepomegranate, formerly classed in a separate familyPunicaceae. The family also includes the widely cultivatedcrape myrtle trees. Botanically, the leaves are usually in pairs (opposite), and the flower petals emerge from the rim of thecalyx tube. The petals often appear crumpled.
Lythraceae species are most often herbs, and less often shrubs or trees; the shrubs and trees often have flaky bark.[6] 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.[5][7][8]
The leaves generally have anopposite arrangement, but sometimes arewhorled oralternate. They aresimple with smooth margins andpinnate venation.[5] Stipules are typically reduced, appearing as a row of minute hairs,[5] or absent.[6]
The flowers are bisexual,radially or occasionallybilaterally symmetric, with a well-developedhypanthium. The flowers are most commonlyquadimerous but can be heximerous, with four to eight sepals and petals. The sepals may be distinct, partially fused to form a tube, or touching without overlapping. The petals are crumpled in the bud and wrinkled at maturity, and are typically distinct and overlapping; they are occasionally absent.[5] Usually, twice as many stamens as petals are seen, arranged in two whorls, and the stamens are often unequal in length. Occasionally, the stamens are reduced to one whorl, or are more numerous with multiple whorls.[4] The ovary is typicallysuperior, infrequentlysemi-inferior,[9] or rarelyinferior. The two to many carpels can be fused together (syncarpous), with two to numerous ovules in eachlocule, with axile placentation of the ovules.[5]
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.[5]
The fruit is usually a dry,dehiscent capsule, occasionally aberry. The seeds are usually flattened and/or winged, with a multilayered outerintegument.[5]Epidermal hairs that expand and become mucilaginous when wet are found in about half the genera.[4]
The Lythraceae are widely distributed, but with most species tropical and some temperate.[4][5] They are absent from theSahara and most arid regions of Australia.[4] Many species occur in aquatic or semi-aquatic habitats (Decodon,Didiplis,Rotala,Sonneratia,Trapa).[5][6] 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.[10]
Edible crops include thepomegranate (Punica granatum) and thewater caltrop (Trapa bicornis orT. natans). The pomegranate is cultivated for the fleshyarils 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, includingCuphea,Lagerstroemia (crape myrtles), andLythrum (loosestrifes).[5]
Purple loosestrife (Lythrum salicaria) is an invasive exotic weed of wetlands throughout Canada and the United States.[11]
Within the orderMyrtales, the family Lythraceae is most closely related to theOnagraceae, with theCombretaceae sister to both families.[5][9] Molecular phylogeny work has led to the inclusion of the formerly recognized families Duabangaceae, Punicaceae, Sonneratiaceae, and Trapaceae.[9]
Lythraceae consists of 28 genera[3] in five subfamilies:
Authority:de Jussieu exWalker-Arnott, 1832; previously 'Lythraceaesensu stricto'[12]
{{cite journal}}: CS1 maint: multiple names: authors list (link)
| International | |
|---|---|
| National | |
| Other | |
