Buttercup petals are usually glossy bright yellow or white and are spirally arranged in the shape of a bowl. Although distributed throughout the world, these flowering plants are especially common in woods and fields of northern temperate zones. Its genus nameRanunculus means little frog — a tribute to the many aquatic varieties of buttercup plants. About 200 species comprise the buttercup family Ranunculaceae, which includes a few shrubs and vines. The deeply cut leaves are said to resemble a crow's foot, which is another common name for the buttercup. Nearly all buttercups contain alkaloid compounds that are poisonous and can be fatal to humans, pets, and livestock. Well-known buttercup varieties include the marsh marigold and peony.