Anagallis arvensis is commonly known as scarlet pimpernel, red pimpernel, or poor man's weatherglass. This small and low-growing annual plant has bright red or orange flowers, and its leaves are arranged in opposite pairs. The name "pimpernel" comes from the Latin word "pimpinella," which means "little pepper," and it is believed to refer to the plant's spicy taste and medicinal properties. Scarlet pimpernel is also known as "shepherd's barometer" because its flowers close when bad weather is approaching. Other names for Anagallis arvensis include "creeping pimpernel," "red chickweed," "red weed," and "rashweed." Despite its pretty appearance, this plant can be toxic if ingested in large quantities.