Scarlet Pimpernel

Scarlet Pimpernel (Anagallis arvensis is a low-growing annual plant found in Europe, Asia and North America. The barometer common names have their origin in the fact that the flowers close when atmospheric pressure decreases and bad weather is approaching.

This common European plant is generally considered a weed and is an indicator of light soils. Scarlet Pimpernel has weak sprawling stems growing to about 50 cm long, which bear bright green ovate sessile leaves in opposite pairs. The small orange, red or blue flowers are produced in the leaf axils from spring till autumn. The petal margins are somewhat crenate and have small glandular hairs. Blue-flowered plants are common in some areas, such as the Mediterranean region, and should not be confused with the related Blue Pimpernel, Anagallis foemina, sometimes treated as a subspecies, Anagallis arvensis ssp. foemina. In 2007, a molecular phylogenetic study showed that Anagallis foemina is more closely related to Anagallis monelli than to Anagallis arvensis, and should be treated as a separate species.

Source: en.wikipedia.org/wiki/Anagallis_arvensis - 13.06.2010