Nick Upton / 2020VISION / Queen Hornet (Vespa crabro) feeding on Knotweed flower (Persicaria bistorta "superba") in garden, Wiltshire, England, UK, May . Property released.

Robert Thompson / Engrailed moth (Ectropis crepuscularia) camouflaged on tree trunk, River Bann Banbridge, County Down, Northern Ireland.

Robert Thompson / Engrailed moth (Ectropis crepuscularia) camouflaged on tree trunk, River Bann Banbridge, County Down, Northern Ireland.

Robert Thompson / Engrailed moth (Ectropis crepuscularia) camouflaged on tree trunk, River Bann Banbridge, County Down, Northern Ireland.

Robert Thompson / Engrailed moth (Ectropis bistortata) resting, Annagariff Wood National Nature Reserve, Peatlands Park, County Armagh, Northern Ireland, UK. April.

Paul Harcourt Davies / Bistort flowers (Persicaria bistortum), Piano Grande, Sibillini, Umbria, Italy. June 2016

Paul Harcourt Davies / Bistort (Persicaria bistortum) flower with hoverfly, Piano Grande, Sibillini, Umbria. June.

Nick Upton / Meadow bistort (Bistorta officinalis / Polygomum bistorta) flowering in profusion on Piva plateau, near Trsa, Montenegro, July.

Robert Thompson / Bistort (Polygonum bistorta) near Lac du Bornon, Mercantour National Park, Provence, France, June.

Radomir Jakubowski / European bistort (Bistorta officinalis) flower, Vosges Mountains, France, June.

Konrad Wothe / Mass of Polygonum flowers ( Polygonum bistorta) low angle view, Upper Bavaria, Germany. May

Christophe Courteau / Bistort {Polygonum bistorta} flowers, Botanic gardens, Berlin, Germany