Carex binervis, the green-ribbed sedge, is a European species of sedge with an Atlantic distribution. It is found from Fennoscandia to the Iberian Peninsula, and occurs in heaths, moorland and other damp, acidic environments. It typically grows to a height of , and has inflorescences comprising one male and several female spikes, each up to long. The utricles have two conspicuous green veins, which give rise to both the scientific name and the common name of the species. In the vegetative state, it closely resembles C. bigelowii, a species that usually grows at higher altitude. C. binervis was first described by James Edward Smith in 1800, and is classified in Carex sect. Spirostachyae; several hybrids with other Carex species are known. Description Vegetative parts The culms of Carex binervis are tall, although typically less than . They are triangular in section with rounded corners and often a single furrow. The leaves are long and wide, light green and shiny on the underside, but dark green and matt on the upper surface. The leaves are flat or slightly keeled, and taper abruptly to a fine point. The roots of C. binervis are in diameter, with the root hairs mostly occurring on the short lateral rootlets. The rhizomes run below the soil surface, and are light brown and approximately in diameter. The whole root system reaches a maximum depth of , spreading more widely than Juncus squarrosus, another dominant plant in Atlantic wet heaths. In the vegetative state, C. binervis is difficult to distinguish from C. bigelowii, a species that tends to grow at higher altitudes than C. binervis. They differ in that C. bigelowii has glaucous leaves and purplish-brown scales on the rhizome, whereas C. binervis has orange-brown rhizome scales, and leaves which are not glaucous. The leaves of C. binervis also develop "wine-red" patches on aging, which are never seen in C. bigelowii. Reproductive parts The inflorescence of C. binervis may be up to half the length of the stem. The lower bracts resemble the leaves, while the upper bracts are more like the glumes. The inflorescence comprises a single terminal male spike, and 2–4 lateral female spikes. The male spike is long, with purplish glumes which are long and have a paler midrib. The female spikes are long and cylindrical. Their peduncles are half sheathed, and up to long, such that the lower female spikes tend to be nodding,