It typically grows to a height of 15–120 cm (6–50 in), and has inflorescences comprising one male and several female spikes, each up to 45 mm (1.8 in) long.

The whole root system reaches a maximum depth of 18 cm (7.1 in), spreading more widely than Juncus squarrosus, another dominant plant in Atlantic wet heaths.

[4] Carex binervis has an oceanic distribution, occurring only in areas of high rainfall, from Finland and Norway, through the British Isles, Germany, Belgium and France, to Spain and Portugal.

[6] Within the British Isles, Carex binervis has a westerly and northerly distribution, and is more abundant in Scotland, Wales and Ireland than in England.

[11] After the Latin diagnosis of Carex binervis, Smith writes:[11] This species appears to have been confounded with C. distans; and from Lightfoot's description of the green angles of the fruit, I presume it to have been what he intended under that name.

It is considerably larger than the real distans, the spikes black intermixed with green rather than yellowish, and the female ones often branched or compounded at their base.

Its most essential and decisive character however consists in the two strong deep-green nerves or ribs which run along each side of the fruit externally near the edge.