Albizia julibrissin, the Persian silk tree, pink silk tree, or mimosa tree, is a species of tree in the family Fabaceae, native to southwestern Asia and eastern Asia. The genus is named after the Italian nobleman Filippo degli Albizzi, who introduced it to Europe in the mid-18th century. It is sometimes incorrectly spelled Albizzia. The specific epithet julibrissin is a corruption of the Persian word (), which means "silk flower" (from "flower" + "silk"). Albizia julibrissin was described by Antonio Durazzini. John Gilbert Baker used the same scientific name to refer to Prain's Albizia kalkora, the Mimosa kalkora of William Roxburgh. Names Albizia julibrissin is known by a wide variety of common names, such as Persian silk tree and pink siris. It is also called Lankaran acacia or bastard tamarind, though it is not too closely related to either genus. The species is called Chinese silk tree, silk tree or mimosa in the United States, which is misleading—the former can refer to any species of Albizia which is most common in any one locale; and, although once included in Mimosa, neither is it very close to the Mimoseae. To add to the confusion, several species of Acacia, notably Acacia baileyana and Acacia dealbata, are also known as "mimosa" (especially in floristry), and many Fabaceae trees with highly divided leaves are called thus in horticulture. Its leaves slowly close during the night and during periods of rain, the leaflets bowing downward; thus its modern Persian name () means "night sleeper". This tendency also explains the Chinese common name hehuan, which means "shut happy" and symbolizes a happy couple in bed. In Japan its common names are , and which all mean "sleeping tree". Nemu tree is a partial translation of . Description Albizia julibrissin is a small deciduous tree with a broad crown of level or arching branches, growing to tall. Its bark is dark greenish grey, becoming vertically striped with age. Its leaves are large and frond-like: They are bipinnate, divided into 6–12 pairs of pinnae, each with 20–30 pairs of leaflets. Individual leaflets are oblong, long and broad. The true leaves are long and broad. The flowers bloom throughout the summer in dense inflorescences, which resemble starbursts of pink silky threads. The true flowers have small calyx and corolla (except the central ones), with a tight cluster of prominent stamens, 2–3 cm long and white or pink with a