Erect to spreading, tufted perennial with short rhizome. Culms trigonous to triquetrous, very slender, usually scaberulous above, 20–60 cm high, c. 0.5 mm diam. Leaves usually flat, shorter than or exceeding culms, 1.5–3 mm diam. Inflorescence loose, 2–6 cm long, including male portion 3–8 mm long; female glumes persistent, acute, straw-coloured, sometimes tinged red-brown, membranous, faintly few-nerved, 4.5–5.5 mm long; stamens 3; utricles weakly trigonous, narrow-ellipsoid, 5.8–6(–7) mm long, c. 1.5 mm diam., scarcely spreading, glabrous, smooth, greenish-brown or yellow-brown; rachilla produced far beyond mouth of utricle, strongly hooked at the top. Nut weakly trigonous, narrow-ellipsoid, brown, glistening, minutely pustulate, c. 3.5 mm long, c. 1.4 mm diam. Flowers summer.
Carex umbricola very closely resembles C. nemoralis, from which it can be distinguished by the more spreading habit, persistent female glumes, and culms that are usually scaberulous below the inflorescence.
