Arctic willow (Salix arctica). This tiny shrub belongs to the Salicaceae family of flowering plants. It is found in tundra and rocky moorland in Greenland, Canada and the Arctic. It is slow growing, reaching 1-15 centimetres in height and reproduces by growing either male or female flowering clusters known as catkins (erect structures at centre of leaf cluster). Arctic willow is a long-lived plant, living several hundred years. Photographed on Baffin Island, Canada.