A large genus of about 400 species of plants in the Ranunculaceae, which 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. A few have orange or red flowers and occasionally, as in R. auricomus, petals may be absent. The petals are often highly lustrous, especially in yellow species. Buttercups usually flower in April or May but flowers may be found throughout the summer especially where the plants are growing as opportunistic colonisers, as in the case of garden weeds.
