Heather Angel / Tulip tree (Liriodendron tulipifera) flower with orange band to attract bees, produces copious nectar. In visible light. Surrey, England, UK. Native to USA. Focus stacked. Sequence 1/2.

Heather Angel / Tulip tree (Liriodendron tulipifera) flower, pollen and nectar fluorescing in UV light. Surrey, England, UK. Native to USA. Focus stacked. Sequence 2/2.

Ernie Janes / Black poplar (Populus nigra) leaf skeleton macro closeup

Pascal Tordeux / Line of Black poplar trees (Populus nigra) at sunset, Surfontaine, Picardy, France.

Jean E. Roche / Bark of an old Black poplar (Populus nigra) Oppedette Canyon, Provence, France, April 2016.

Alex Hyde / Hybrid Black poplar (Populus x canadensis) leaf detail showing venation. Cambridgeshire, UK. September.

Alex Hyde / Hybrid Black poplar (Populus x canadensis) leaf detail showing venation. Cambridgeshire, UK. September.

Donald M. Jones / Black Bear (Ursus americanus) cub in Aspen (Populus sp) tree, Canada

David Woodfall / Black poplar tree (Populus nigra) by a housing development on a flood plain, Glasdir, Ruthin, Vale of Clwyd, Denbighshire, Wales. November 2012.

Gary K. Smith / Black Poplar (Populus serotina) hybrid plantation. Suffolk, England, May.

Wild Wonders of Europe / Smit / Old growth forest of Black poplar trees (Populus nigra) Gornje Podunavlje Special Nature Reserve, Serbia, June 2009

Martin Gabriel / Black poplar tree (Populus nigra), backlit at sunset, Bavaria, Germany, May 2008