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.Tela Botanica - Carex trinervis
It is found in sandy marshes, damp dune slacks and heaths in coastal areas of Western Europe.Online Atlas of the British and Irish FloraTela Botanica - Carex trinervis In the British Isles it was only ever identified in Ormesby, Norfolk, where it became extinct in 1869.Online Atlas of the British and Irish Flora
See also List of extinct plants of the British Isles
References