Carex trinervis
Carex trinervis is a species of sedge which is native to Europe.
It is a perennial herb, which grows to a height of 40 cm, has glaucous leaves and spreads by stolons. It bears 2-3, sessile, oblong inflorescences per shoot.
It is found in sandy marshes, damp dune slacks and heaths in coastal areas of Western Europe. In the British Isles it was only ever identified in Ormesby, Norfolk, where it became extinct in 1869.