Clump-forming perennial with short rhizome. Culms rigid, erect, flat or with one surface slightly convex, glabrous, smooth, 35–60 cm high, 2.5–9 mm wide; margins scabrous, viscid (yellowish, turning red) and often ciliate. Leaf-blades similar in form and length to culms, 2–7 mm wide; sheaths straw-coloured or rarely reddish near apex, dark brown to blackish at base, ± viscid, shining. Inflorescence oblong to ovate in outline, erect, occasionally viscid, 7–22 cm long, 1.5–3 cm diam.; involucral bract shorter than inflorescence. Spikelets numerous, 4–7 mm long; glumes 5 or 6, puberulous near apex or glabrous, red-brown to blackish brown, the 2 lowest empty, shorter than fertile glumes, obtuse to acute, mucronate; fertile glumes 4–6 mm long, long-acute; hypogynous scales 6, pale red-brown, to one-quarter length of nut. Nut narrow-ellipsoid to narrow-ovoid, pale to dark brown, smooth, shining, 2.3–3.0 mm long, 1.2–1.5 mm diam. Flowers spring–summer.
LoM, MuM, Wim, GleP, VVP, VRiv, RobP, OtP, Gold, CVU, GGr, DunT, NIS, EGL, EGU, HSF. Also WA, SA, Qld, NSW, Tas. On sandy sites in the north-west where common, scattered in rocky areas in the north and a few areas in the east (e.g. Heyfield district, East Gippsland beyond the Snowy River). Occurs in heaths, woodlands and dry open-forest.
In mallee regions of Victoria there is a form or possibly separate taxon which differs from typical L. viscidum in having less viscid, less scabrous, non-ciliate margins, in having more of the leaf-sheath dark-coloured, and with the culm surface rather like that of L. sieberi. This form occurs also in far south-west NSW and adjacent areas of SA.
