Pimpernel

a genus of plants belonging to the primrose family. The common pimpernel grows in waste, sandy lands. It has been introduced into eastern North America from Europe. It has a wheel-shaped, five-pointed corolla, with almost no tube. The flowers vary from scarlet and purple to blue and white. They close quickly at the approach of bad weather. The popular name in England is "poor man's weather glass." "The weather-wise pimpernel," say the poets.