This article is about the flower. For other definitions, see Buttercup (disambiguation).

over 400; see text

Ranunculus is a large genus of about 400 species of plants in the Ranunculaceae. It includes the buttercups, spearworts, water crowfoots and the lesser celandine (but not the greater celandine of the poppy family Papaveraceae).

They are mostly herbaceous perennials with bright yellow or white flowers (if white, still with a yellow centre); some are annuals or biennials, and a few have orange or red flowers.

The Water crowfoots (Ranunculus subgenus Batrachium), which grow in still or running water, are sometimes treated in a separate genus Batrachium. They have two different leaf types, thread-like leaves underwater and broader floating leaves.

All Ranunculus species are poisonous when fresh to cattle and other livestock, but their acrid taste means they are usually left uneaten. Poisoning can occur where buttercups are abundant in overgrazed fields where little other edible plant growth is left, and the animals eat them out of desperation. The poisons are degraded by drying, so hay containing dried buttercups is safe.

Some species are popular ornamental flowers in horticulture, with many cultivars selected for large and brightly coloured flowers.

An old superstition says that if you hold a buttercup under your face, and yellow light is reflected on your face, it means that you like butter.

Partial species list

Ranunculus acris - Meadow buttercup
Ranunculus aquatilis - Common water crowfoot
Ranunculus arvensis - Corn buttercup
Ranunculus asiaticus - Persian buttercup
Ranunculus auricomus - Goldilocks buttercup
Ranunculus bulbosus - Bulbous buttercup
Ranunculus ficaria - Lesser celandine
Ranunculus flamula - Lesser spearwort
Ranunculus fluitans - River water crowfoot
Ranunculus glacialis - Glacier buttercup
Ranunculus lingua - Greater spearwort
Ranunculus peltatus - Pond water crowfoot
Ranunculus platanifolius - Large white buttercup
Ranunculus sceleratus - Celery-leaved buttercup
Ranunculus repens - Creeping buttercup
and many more