Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

s, found primarily on moist soils in cold and temperate regions. Most species are known as willow, but some narrow-leaved shrub species are called osier, and some broader-leaved species are referred to as sallow (from

Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlement of Britain, Anglo ...

''sealh'', related to the Latin word ''salix'', willow). Some willows (particularly arctic and

alpine Alpine may refer to any mountainous region. It may also refer to: Places Europe * Alps, a European mountain range ** Alpine states, which overlap with the European range Australia * Alpine, New South Wales, a Northern Village * Alpine National Pa ...

species) are low-growing or creeping shrubs; for example, the

dwarf willow ''Salix herbacea'', the dwarf willow, least willow or snowbed willow, is a species of tiny creeping willow (family Salicaceae) adapted to survive in harsh arctic and subarctic environments. Distributed widely in alpine and arctic environments ar ...

(''Salix herbacea'') rarely exceeds in height, though it spreads widely across the ground.

Description

Willows all have abundant watery

bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, ...

sap, which is heavily charged with

salicylic acid</