See Botany Index. There is only one species known, which grows naturally in moist boggy lands in many parts of England and Scotland. The flowers gathered before they expand, and preserved in salted vinegar, are a good substitute for capers. The juice of the petals, boiled with a little alum, stains paper yellow. The remarkable yellowness of the butter in spring is supposed to be caused by this plant; but cows will not eat it, unless compelled by extreme hunger; and then, Boerhaave says, it occasions such an inflammation, that they generally die. Upon May-day, the country people strew the flowers upon the pavement before their doors. Goats and sheep eat this plant; horses, cows, and swine, refuse it.