Better know as scarlet pimpernel, this flower was found in the woodland preservers of Southeastern Pennsylvania. Commonly found in Europe, this plant is mostly considered a weed. Native to Europe, Western Asia and North Africa, the pimpernel was introduced to North America by the early European settlers. The scarlet pimpernel flower only opens in direct sunlight. The plant is toxic to livestock, poultry, and dogs. Grazing livestock avoid this plant due to the bitter and acrid taste.