Sven Zacek / Wood sorrel (Oxalis acetosella) flowers, Southern Estonia.

Sven Zacek / Wood sorrel (Oxalis acetosella) flowering on forest floor of boreal forest. Tartumaa, Southern Estonia. May.

SCOTLAND: The Big Picture / Wood sorrel (Oxalis acetosella) leaves at base of tree in ancient Ash (Fraxinus excelsior) woodland in spring. Rassal Ashwood National Nature Reserve, Highlands, Scotland, UK.

Andy Sands / Wood sorrel (Oxalis acetosella) two flowers after a rain shower, Suffolk, England, UK, April

Konrad Wothe / Common wood sorrel (Oxalis acetosella) and fern, Bavarian Forest National Park, Germany, May.

Robert Thompson / Wood sorrel (Oxalis acetosella) Co. Armagh, Northern Ireland.

Alex Hyde / Wood sorrel (Oxalis acetosella) growing on woodland floor. Plitvice Lakes National Park, Croatia. November.

Fabrice Cahez / Common wood sorrel (Oxalis acetosella) leaves, Vosges, France, May.

David Tipling / Common wood sorrel (Oxalis acetosella) and Bluebells on woodland floor. Foxley Wood National Nature Reserve, Norfolk, UK, April 2014.

Guy Edwardes / 2020VISION / Common wood sorrel (Oxalis acetosella) in flower, New Forest National Park, Hampshire, England, UK, April.

Wild Wonders of Europe / Bartocha / Mixture of ground plants including Common wood sorrel (Oxalis acetosella), Herb Robert (Geranium robertianum), Maidenhair spleenwort (Asplenium trichomanes) Sweet woodruff (Galium odoratum) Wild straw...

Laurie Campbell / Wood sorrel (Oxalis montana) flowering, Argyll, Scotland, April

Laurie Campbell / Wood sorrel (Oxalis montana) leaves covered in rain driops, Morayshire, Scotland, April

Laurie Campbell / Wood sorrel (Oxalis montana) flowering, Argyll, Scotland, April

Ernie Janes / Wood-sorrel (Oxalis montana) leaves. UK, April.

Colin Varndell / Wood sorrel (Oxalis montana) in flower, Dorset, UK, April

Colin Varndell / Wood-sorrel flowers (Oxalis montana) Kingcombe Meadows, Dorset, UK

Sven Zacek / Wood sorrel (Oxalis montana) flowering in woodland, in Spring, Estonia

Robert Thompson / Wood sorrrel {Oxalis montana} Clare Glen, Tandragee, County Armagh, Northern Ireland, UK

Robert Thompson / Wood sorrrel {Oxalis montana} Clare Glen, Tandragee, County Armagh, Northern Ireland, UK

Robert Thompson / Wood sorrrel {Oxalis montana} Clare Glen, Tandragee, County Armagh, Northern Ireland, UK

Laurie Campbell / Wood Sorrel (Oxalis montana) Argyll, Scotland, April

Laurie Campbell / Wood Sorrel (Oxalis montana) growing on Oak tree, Argyll, Scotland, April

Russell Cooper / Wood Sorrel (Oxalis montana) flower, Banstead Wood SSSI, Surrey. UK

Ross Hoddinott / Wood sorrel (Oxalis acetosella) leaves, Lanhydrock, Cornwall, UK. March 09.

Martin Gabriel / Wood sorrel leaves {Oxalis montana} Germany

Jose B. Ruiz / Wood sorrel {Oxalis montana} in flower, Spain

Jose B. Ruiz / Wood sorrel {Oxalis montana} Alicante, Spain.

Kirkendall-Spring / Wood Sorrel {Oxalis montana} growing on the forest floor, Olympic NP, Washington, USA

Adrian Davies / Wood sorrel in flower (Oxalis montana) Southern England, UK

Konstantin Mikhailov / Wood Sorrel (Oxalis montana) in swamps of SE Siberia, Russia, June

Konstantin Mikhailov / Wood Sorrel (Oxalis montana) in swamps of SE Siberia, Russia,

Peter Cairns / Wood sorrel leaves (Oxalis acetosella), Scotland, UK.

Tony Evans / Wood sorrel leaves {Oxalis montana} UK

Asgeir Helgestad / Wood sorrel leaves{Oxalis montana} growing on mossy tree-trunk Norway

Robert Thompson / Wood sorrel (Oxalis montana) flower, Clare Glen, County Armagh, Northern Ireland, UK

Paul Harcourt Davies / Wood sorrel (Oxalis acetosella). Dolemites, Italy. June.

Linda Pitkin / Wood sorrel (Oxalis acetosella) Shere Woodlands (SWT) Surrey, England, April 2014.