John Shaw / Hybrid Poplar tree plantation in autumn (Populs sp.). Boardman Tree Farm, near Irrigon, Oregon, USA. October.

John Shaw / Abandoned house in middle of a wheat field. Palouse farming area, south eastern Washington, USA, August.

Nigel Cattlin / Common knotgrass (Polygonum aviculare) growing as arable weed. England, UK. August.

Nigel Cattlin / Redshank (Persicaria maculosa) growing as arable weed. England, UK. September.

Nigel Cattlin / Redshank (Persicaria maculosa) growing as arable weed. England, UK. September.

Nigel Cattlin / Redshank (Persicaria maculosa), an annual arable weed. Berkshire, England, UK. August.

Heather Angel / Alexander's rhubarb (Rheum alexandrae) and Dwarf purple rhododendron (Rhododendron impeditum) in wet valley. Large bracts on rhubarb protect tiny flowers from UV rays. Near Lake Kangding Xian Cuo,...

Heather Angel / Alexander's rhubarb (Rheum alexandrae) and Dwarf purple rhododendron (Rhododendron impeditum) in wet valley with low cloud. Large bracts on rhubarb protect tiny flowers from UV light. Near Lake Ka...

SCOTLAND: The Big Picture / Sheep's sorrel, (Rumex acetosella), in unimproved grassland, Cairngorms National Park, Scotland, UK, July.

SCOTLAND: The Big Picture / Sheep's sorrel, (Rumex acetosella), in unimproved grassland, Cairngorms National Park, Scotland, UK, July.

SCOTLAND: The Big Picture / Sheep's sorrel, (Rumex acetosella), in unimproved grassland, Cairngorms National Park, Scotland, UK, July.

Ernie Janes / Red bistort (Persicaria) 'Hohe Tatra' cultivated plant.