Corn buttercup Ranunculus arvensis

Status Red - Endangered & Critically Endangered
Best Time to See May, June
Colour Yellow
Habitat Arable, Farmland

A smaller relative of the more common buttercups with a paler lemon-yellow hue.

However, it's the seeds which are the most impressive and characteristic element of this flower: they are large (up to almost a centimetre long - quite a size for such a small plant), oval and covered in vicious spines up to 2mm in length.

Corn buttercup leaves are stalked and deeply dissected, divided into 3-5 lobes.


Formerly widespread throughout the south and east of England but has declined rapidly over the last 60 years, now with few viable populations. A strong-hold remains in the south-west Midlands, with other sites scattered from Devon to Suffolk.


An arable species, it is typically found in the margins of fields sown with winter cereals. It is found most frequently on calcareous and heavy clay soils.

Best time to see

Flowers from May to mid June.


It is classified as ‘Critically Endangered’ and is therefore considered to be facing an extremely high risk of extinction in the wild. Listed as a priority species under the UK Biodiversity Action Plan.

Key threats

The main causes of decline are a direct result of the intensification of arable farming, key factors being improved seed cleaning of all arable crops, the introduction of broad-spectrum herbicides and the density of modern crops, with R. arvensis competing poorly with a fully fertilised crop.

Did you know?

The sharp spines on the seed-heads have earned the plant its local names of devil's claws and hellweed. Other local names follow the same theme: devil-on-both-sides, devil-on-all-sides, devil's coach wheel and devil's currycombs, describing the achenes which stick out all around the mature fruit. It is also called crowclaws and horse-gold in Yorkshire, but better known as eggs and bacon in Cheshire or jackweed in Oxfordshire.

All parts of the plant are poisonous when fresh, and it also has a strongly acrid juice that can cause skin blistering. It has the potential to be a weed of cornfields.