Buttercup, Meadow buttercup, Ranunculus acris, Single yellow flower growing outdoor amid green foliage.

Buttercup, Meadow buttercup, Ranunculus acris, Yellow flowers in a meadow in Upper Teesdale, North Pennines, Co Durham.

Buttercup, Meadow buttercup, Ranunculus acris, Yellow flowers in a meadow in Upper Teesdale, North Pennines, Co Durham.

Buttercup, Meadow buttercup, Ranunculus acris, Yellow flowers in a meadow in Upper Teesdale, North Pennines, Co Durham.

Buttercup, Meadow buttercup, Ranunculus acris, Mass of small yellow coloured flowers growing outdoor.

Lesser celandine, Ranunculus ficaria 'Brazen Hussy', Several open daisy shape yellow flowers with yellow stamens.

Lesser celandine, Ranunculus ficaria 'Brazen Hussy', Several open daisy shape yellow flowers with yellow stamens.

Ranunculus, Persian buttercup. Ranunculus asiaticus, Single pink coloured flower opening with another soft focus behind.

Ranucuclus, Persian buttercup, a Ranunculus asiaticus, dark pink flower against a solid black background.

Ranucuclus, Persian buttercup, a Ranunculus asiaticus, black and white against a solid black background.

Ranucuclus, Persian buttercup, a Ranunculus asiaticus, pink flower against a pink background.

Ranucuclus, Persian buttercup, a Ranunculus asiaticus, orange flower against a solid black background.