Carex diandra

Perennial, narrow-leaved, loosely cespitose herb.

20–60 cm high.

The stem is erect, with continuous pith, scabrous, nearly terete at the base and obtusely triangular at the summit.

The basal leaf sheaths are gray-brown or black-brown, faintly lustrous and entire. The leaves are sessile, sheathed and slightly shorter than the culm. The lamina is narrow, 2–4 mm wide and gray-green.

The inflorescence consists of 5–10 spikes, and is 2–4 cm long, rather dense, terete and unbranched. The spikes are fusiform, sessile or the most proximal ones have a short peduncle. Spikes consist of both pistillate and staminate flowers. The staminate flowers are located at the summit of the spike. The pistillate flowers are located at the base of the spike. A staminate flower has three stamens. A pistillate flower has two stigmas and it is surrounded by a perigynium. The pistillate scales are 2–3 mm long, light brown or maroon and with a hyaline margin. A perigynium is 2–3 mm long, lustrous and brown. There are two thick veins on the dorsal side at the base of the perigynium. The beak is long and dentate.

The fruit is an achene which matures inside the perigynium.