Nigel Cattlin / Common hemp-nettle (Galeopsis tetrahit) with white flowers and a dark purple calyx on waste ground, Berkshire, UK, July.

Nigel Cattlin / Common hemp-nettle (Galeopsis tetrahit) plants at the end of their flowering on the Axe Estuary Wetlands Nature Reserve in East Devon

Nigel Cattlin / Severe infestation of several broad-leaved weed species in a young wheat crop, Cambridgeshire, England, UK,