Wild Wonders of Europe / Bergman / Dwarf willow (Salix herbacea) and flowering plant, Thingeyjarsyslur, Iceland, June 2009 Licensed for exclusive book cover until 1 February 2015.

John Shaw / Dwarf willow (Salix herbacea) growing beside a small glacial stream with icebergs in Hare Fjord, Scoresby Sund, Greenland, August.

SCOTLAND: The Big Picture / Regenerating Willow (Salix sp) on heather moorland, Glenfeshie, Cairngorms National Park, Scotland, UK, September 2015.

Chris Mattison / Dwarf willow (Salix herbacea) in cultivation, Yorkshire, April.

Chris Mattison / Dwarf willow (Salix herbacea) in cultivation, Yorkshire, April.

Laurie Campbell / Dwarf / Least willow tree (Salix herbacea) growing between crack in boulder, Isle of Rum National Nature Reserve, Hebrides, Scotland, June

Bruno D'Amicis / Dwarf Willow (Salix herbacea) foliage. Western Tatras, Slovakia, June.

Yva Momatiuk & John Eastcott / Dall's Sheep (Ovis dalli) sub-adult ram nibbling on Dwarf Willow (Salix herbacea), Denali National Park, Alaska

Wild Wonders of Europe / D'Amicis / Mat of Dwarf willow treees (Salix herbacea) saddle in the Liptovske kopi, Western Tatras, Carpathian Mountains, Slovakia, June 2009

Elio Della Ferrera / Dwarf willow plants {Salix herbacea} leaves and flowers, Tessa Regional Park, Alps, Italy

Niall Benvie / Bog / Northern bilberry {Vaccinium uliginosum} berries amongst Dwarf willow {Salix herbacea} Norway

Erlend Haarberg / Dwarf willow (Salix herbacea), Jotunheimen National Park, Norway, July.