Osier
Osier, A shrub or small tree of the willow family. The common osier, which grows to a height of 25 feet (8m), is native to temperate regions of Asia and Europe. It was brought to North America by the colonists and now grows wild in New England and eastern Canada. It has narrow, smooth-edged leaves from 4 to 10 inches (10 to 25 cm) long, with white hairs on the undersides. After the Osier willow has been severely cut back, it forms long, flexible twigs ideal for basket weaving.
Several other species of willow and several dogwoods are also called osiers. The term is also used for willow shoots and for any long, flexible twigs suitable for basket weaving and wickerwork.
The common osier willow is Salix viminalis of the willow family, Salicaceae.