Willows, also called sallows and osiers, of the genus Salix, comprise around 350 species of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions.
Willow
At the base of the petiole a pair of stipules form. These may fall in spring, or last for much of the summer or even for more than one year (marcescence).
Young male catkin
Pollard willow and woodpile in the Bourgoyen-Ossemeersen, Ghent, Belgium
Bark is the outermost layer of stems and roots of woody plants. Plants with bark include trees, woody vines, and shrubs. Bark refers to all the tissues outside the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner bark, which in older stems is living tissue, includes the innermost layer of the periderm. The outer bark on older stems includes the dead tissue on the surface of the stems, along with parts of the outermost periderm and all the tissues on the outer side of the periderm. The outer bark on trees which lies external to the living periderm is also called the rhytidome.
The bark of Pinus thunbergii is made up of countless shiny layers.
Damaged bark of a cherry tree
Living tree bark enveloping barbed wire
Bark of mature mango (Mangifera indica) showing lichen growth
