Lysimachia tenella

Delicate pimpernel, or Bog pimpernel. Small creeping perennial of the Primulaceae family (formerly Myrsinaceae according to recent classifications), native to Western and Atlantic Europe, present in France mainly in regions with high rainfall: Brittany, Normandy, Basque Country, Western Massif Central, where it colonizes bogs, seepages, spring edges, wet meadows, and sphagnum bogs, always on acidic, waterlogged substrates poor in nutrients.

It develops threadlike, creeping stems that root at the nodes, forming loose and delicate mats only a few centimeters high. The leaves are small, oval-rounded, sessile, opposite, of a tender and bright green. The flowers, borne individually on fine peduncles, are funnel-shaped, with five petals, of a pale pink to delicate flesh pink, slightly veined, and emit a sweet and discreet fragrance, surprising for such a modest plant. The flowering extends from June to August.

Its ecology strictly linked to acidic wet environments makes it an indicator plant of the quality of peat bogs, which are declining in many regions due to agricultural drainage and the destruction of bogs. It is protected in several French departments.