Donald M. Jones / Steller's Jay (Cyanocitta stelleri) in autumn, Troy, Montana

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.

Juan Manuel Borrero / Carambola or Starfruit (Averrhoa carambola). Mexico

Ernie Janes / Bank of Oxeye daisies (Oxalis sp) and Bluebells (Hyancinthoides) in which major gas pipeline runs Norfolk, UK, May.

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

Tony Phelps / Yellow-eyed sorrel (Oxalis obtusa) DeHoop Nature Reserve, Western Cape, South Africa.

Chris Mattison / Creeping wood sorrel (Oxalis corniculata) flowers. Derbyshire, England, UK, September.

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

Pascal Pittorino / Pink sorrel / Wood sorrel (Oxalis articulata) with dew drops on petals, Var, Provence, France, May.

Konrad Wothe / Carambola (Averrhoa carambola) blooming, Peru

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

Tony Phelps / Grand Duchess sorrel (Oxalis pes-caprae) and Hedgehog lily (Massonia sp.) De Hoop Nature Reserve, Western Cape, South Africa.

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

RHONDA KLEVANSKY / Three Bermuda buttercups (Oxalis pes caprae) in flower, Namaqualand, South Africa, August.

Jack Dykinga / Towering Coastal redwoods (Sequoia sempervirens) rising from forest understory of Wood sorrel (Oxalis), Prairie Creek Redwoods State Park, California, May.

Paul Harcourt Davies / Wildflowers, from left to right Barbary nut (Gynandriris sisyrinchium) Scarlet Tulip (Tulipa doerfleri) and Buttercup oxalis (Oxalis pes-caprae) Gious Kambos, Crete, 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...

Jim Brandenburg / Violet Wood-sorrel (Oxalis violacea) flower, Minnesota

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

Gerry Ellis / Woodsorrel (Oxalis sp) and Coast Redwood (Sequoia sempervirens) leaf litter, Pacific coast, North America

Jim Brandenburg / Violet Wood Sorrel (Oxalis violacea), tallgrass prairie, Minnesota.

Claudio Contreras / Broadleaf woodsorrel (Oxalis latifolia) in flower, close up. Milpa Alta forest, outskirts of Mexico City, Mexico. August.

John Shaw / Sword ferns (Polystichum munitum) at the base of Sitka spruce (Picea sitchensis) with Oregon oxalis ground cover (Oxalis oregana). Hoh Rainforest, Olympic National Park, Washington, USA, June.

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

Linda Pitkin / Procumbent yellow-sorrel (Oxalis corniculata) Molesey Cemetery, West Molesey, Surrey, England, May.

Linda Pitkin / Pink-sorrel (Oxalis articulata), South West Coast Path?, Wembury, near Plymouth, Devon, England, July.

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