Salix alba (white willow) is a species of willow native to Europe and western and central Asia. The name derives from the white tone to the undersides of the leaves.

Source: http://en.wikipedia.org/wiki/Salix_alba
Photo by: André Karwath CC BY-SA 2.5

Photo by:
1. LoggaWiggler
2. C. Weber freeimages.com

Photo by: Willow GFDL, CC-BY 2.5

Photo by: Willow GFDL, CC BY 2.5