Willows, also called sallows and osiers, of the genus Salix, comprise around 350 species of typically deciduous trees and shrubs. They are primarily found on moist soils in cold and temperate regions.
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